Method of object transfer for a heat treatment system

ABSTRACT

Disclosed herein is method for use in a vertical heat treatment system which has an opening which is formed in a partition wall separating a housing-box transfer area from a treating-object transfer area (a wafer transfer area), and and through which an object to be treated is carried in the vertical heat treatment system to carry out a predetermined treatment. When the object to be treated is carried in via the opening of the partition wall, which separates the housing-box transfer area from the treating-object transfer area (wafer transfer area), to carry out a predetermined treatment, the structure of various mechanisms in the vicinity of the opening is simplified, and the space is saved.

CROSS REFERENCE TO RELATED APPLICATION

This application is a division of application Ser. No. 11/705,443, filedFeb. 13, 2007 which is a division of application Ser. No. 10/939,432,filed Sep. 14, 2004 which is a division of application Ser. No.09/934,756, filed Aug. 23, 2001, which are incorporated herein byreference in their entirety.

TECHNICAL FIELD

The first invention relates generally to a vertical heat treatmentsystem utilizing a treating-object housing box for airtightly housingtherein objects to be treated, such as semiconductor wafers.

The second invention relates to a vertical heat treatment system usedfor carrying out a treatment, such as oxidation, diffusion, annealing orCVD, for objects to be treated, such as semiconductor wafers, and amethod for controlling the same.

The third invention relates to a vertical heat treatment system forheat-treating objects to be treated, and a method for transferringobjects to be treated, and more specifically, relates to a vertical heattreatment system and treating-object transferring method which arecapable of aligning a holder for holding objects to be treated.

The fourth invention relates to a heat treatment system for use in stepsof fabricating a semiconductor device or the like.

BACKGROUND ART

The background of the first invention will be described below.

In general, in order to fabricate a semiconductor integrated circuit,such as an IC or LSI, various deposition, oxidation and diffusion, andetching processes are repeatedly carried out for a semiconductor wafer.When the respective processes are carried out, it is required totransfer the semiconductor wafer between corresponding systems. In thiscase, as well known, in order to improve the yields, it is required toprevent particles and natural oxide films from adhering to the surfaceof the semiconductor wafer. Therefore, with the increase of the requestfor high scale down and high density integration, a closedtreating-object housing box tends to be used for transferring the wafer.As shown in FIGS. 5 and 6, a treating-object housing box 2 has anopening portion 4 on one end thereof, and a substantially semi-circularbox vessel 6 on the other end thereof. Multistage supporting protrusions8 are provided on the inner wall of the box vessel 6, and the peripheralportions of semiconductor wafers W are mounted and supported thereon, sothat the semiconductor wafers W can be housed therein on multiple stagesat substantially even intervals. On the ceiling portion of the boxvessel 6, a gripping handle 24 for holding the whole vessel is provided.Usually, one box can house therein about 25 or 13 wafers.

A rectangular hollow plate-shaped lid 10 is detachably mounted on theopening portion 4 of the box vessel 6. The interior of the box vessel 6is evacuated in an airtight state to some extent, to be in an atmosphereof an inert gas, such as N₂ gas, so that the wafers W housed therein donot contact outside air as much as possible.

The lid 10 is provided with two locking mechanisms 12. By releasing thelocking mechanism 12, the lid 10 can be removed from the opening portion10.

Specifically, as shown in FIG. 7, each of the locking mechanisms 12 hasa rotatable disk-shaped locking plate 14 at the substantially center ofthe lid 10 in height directions. The locking plate 14 is formed with anelongated recessed key groove 16. Above and below the locking plate 14,there are provided a pair of rising and setting pins 20, each of whichis connected to an arm 18 as a crank mechanism for converting a circularmotion into a linear motion. By rotating the locking plates 14 by 90degrees in normal and reverse directions, the upper and lower rising andsetting pins 20 rise and set in vertical directions.

During locking, as shown in FIG. 6, the tips of the rising and settingpins 20 are inserted into and engaged with pin holes 22, which areformed in top and bottom edge portions for defining the opening portion4 (only the bottom edge portion is shown in FIG. 6), to prevent the lid10 from being removed from the opening portion 4. Therefore, if keymembers (not shown) are engaged with the corresponding key grooves 16 tobe rotated by 90 degrees from a locked state shown in FIG. 7(A) toretract the rising and setting pines 20 by a distance ΔL as shown inFIG. 7(B) to pull them out of the pin holes 22 (see FIG. 6), the lid 10is in an unlocked state.

In general, the above described housing box 2 is automaticallytransferred in a treatment system which includes an automatic transfermechanism for the housing box, a stock region for temporarily stockingtherein the housing box, and a treatment unit for treating semiconductorwafers. In addition, key members 26 are operated by automaticapparatuses having them, so that the lid 10 of the housing box 2 isautomatically detached and attached by the above described process.

For example, such a treatment systems is disclosed in Japanese PatentLaid-Open No. 4-180213, Japanese Patent Laid-Open No. 8-279546, JapanesePatent Laid-Open No. 11-274267, and the applicant's prior application(Japanese Patent Application No. 11-201000). To the interior of thesystem, an inert gas, such as N₂ gas, or clean air having a highcleanliness factor is supplied.

Specifically, the interior of the above described treatment system isairtightly separated into a housing-box transfer area for receiving andtemporarily stocking the housing box therein, and a wafer transfer areafor transferring semiconductor wafers, which are taken out of thehousing box after opening the housing box, to a wafer boat or the liketo actually carry out a treatment. The housing-box transfer area isfilled with clean air, and the wafer transfer area is filled with aninert gas, such as N₂, for preventing natural oxide films from beingproduced.

The partition wall for separating both areas from each other has a doorcapable of being open and closed. This door is provided with one or twoopening portions. The housing box is set so as to tightly contact theopening portions. Then, the housing box lid and the door are removedfrom the wafer transfer area to take shelter. In this state, thesemiconductor wafers are fed into the wafer transfer area.

Referring to FIGS. 8 and 9, the state at this time will be describedbelow.

In the case of an example of a conventional system shown in FIG. 8, twostages of upper and lower mounting tables 30A and 30B capable of beingintegrally moved in vertical directions are provided on the side of thehousing-box transfer area of the opening portion 28 of a partition wall26, and a treating-object housing box 2 is mounted thereon to be fixed.An opening/closing mechanism 34 for removing the lid 10 and a door 32for opening and closing the opening portion 28 is provided forsubstantially simultaneously removing the lid 10 and the door 32 and forcausing them to take shelter upwards or downwards while holding them.The opening/closing mechanism 34 is provided with a key portion (notshown) which is inserted into the key groove shown in FIG. 6 to berotated to carry out locking and unlocking.

After the carrying-out of the wafers in one of the housing boxes iscompleted, the lid 10 and the door 32 are mounted again. Thereafter, themounting tables 30A and 30B are caused to integrally slide upwards in,e.g., the shown embodiment, and the wafers are carried out of thehousing box 2, which newly faces the opening portion 28, in the samemanner as that described above.

Furthermore, the reason why the two housing boxes 2 are thus set is thatthe wafer carrying-in/out efficiency is improved.

On the other hand, in the case of an example of a conventional systemshown in FIG. 9, the partition wall 26 is provided with upper and loweropenings 28A and 28B which are provided with doors 32A and 32B foropening and closing them, respectively. Inside of the housing-boxtransfer area of the openings 28A and 28B, mounting tables 30A and 30Bare fixedly mounted, respectively. Inside of the wafer transfer area ofthe openings 28A and 28B, two opening/closing mechanisms 34A and 34B areprovided so as to correspond to the openings 28A and 28B, respectively.In the same manner as that described above, the lid 10 and the door 32Aor 32B are removed from the housing box, which is set on each of theopenings 28A and 28B, by means of the opening/closing mechanisms 34A and34B. Furthermore, these opening/closing mechanisms are disclosed inJapanese Patent Laid-Open No. 11-274267, which has been described aboveas the prior art, and so forth.

By the way, in the above described examples of conventional systems, twohousing boxes can be set in the vicinity of one or two openings, so thatit is possible to fed the wafers into the wafer transfer area to greatlyimprove the transfer efficiency of the wafers to the wafer boat.

However, in the case of the example of the conventional system shown inFIG. 8, the two mounting tables 30A and 30B are provided so as to beslidable in vertical directions. Therefore, there is a problem in thatit is required to ensure a large space for three housing boxes in thisportion.

In the case of the example of the conventional system shown in FIG. 9,it is sufficient to provide a space for only two housing boxes. However,in this case, there is a problem in that it is required to provide twoopening/closing mechanisms 34A and 34B which have a complicatedstructure and which are relatively expensive, so that the costs arehigh.

In particular, in the case of the opening/closing mechanisms 34A and 34Bshown in FIG. 9, the structure must be complicatedly devised in order toavoid the interference of the opening/closing mechanisms with eachother, so that higher costs are caused.

The background of the second invention will be described below.

In the fabrication of semiconductor devices, various treatments, such asoxidation, diffusion and CVD, are carried out with respect tosemiconductor wafers serving as objects to be treated. As systems forcarrying out such treatments, so-called vertical heat treatment systemsare widely utilized.

As such a vertical heat treatment system, from the standpoint of theimprovement of throughput, there is known a vertical heat treatmentsystem which uses two wafer boats serving as holders for holding aplurality of semiconductor wafers and wherein semiconductor wafers aretransferred with respect to one wafer boat while heat treatment iscarried out with respect to the other wafer boat.

The conventional heat treatment system has a housing which is separatedinto front and rear portions by a partition wall to define a carriertransfer area and a loading area in which a vertical heat treatmentfurnace having an opening in its bottom is provided. The loading areaincludes: a boat elevator which is a lifting mechanism moved in verticaldirections for carrying a wafer boat in and out of the heat treatmentfurnace; a holder mounting portion comprising two boat mounting portionswhich are arranged in the front and rear portions of one side portion ofthe housing; a boat transfer mechanism which is a holder transfermechanism for transferring the wafer boat between the boat mountingportion and the boat elevator; and a wafer transfer mechanism which is atreating-object transfer mechanism for transferring semiconductor waferswith respect to the wafer boat supported on the boat mounting portion.

This vertical heat treatment system has a motion space region in whichthe wafer transfer mechanism and the boat transfer mechanism overlapwith each other. When the semiconductor wafers are transferred, the boattransfer mechanism is moved to a sheltered position below the motionspace region, and when the wafer boat is transferred, the wafer transfermechanism is moved to a sheltered position above the motion spaceregion.

The sheltered position of the wafer transfer mechanism is thus arrangedupwards in the vertical heat treatment system with the above describedconstruction. Therefore, when the wafer boat is carried out of the heattreatment furnace, the wafer transfer mechanism is easy to have theinfluence of heat from the bottom end opening of the heat treatmentfurnace and the wafer boat after the heat treatment, and the temperatureof the wafer transfer mechanism at the sheltered position sometimesreaches to 150° C., so that it is difficult to stably operate the systemfor a long term due to the failure of the control apparatus in the wafertransfer mechanism and so forth.

In recent years, it has been also requested to increase the diameter ofthe semiconductor wafer in order to improve the yields of chips per onesemiconductor wafer. For example, it has been requested that asemiconductor wafer having a diameter of 12 inches (300 mm) isheat-treated.

However, with the increase of semiconductor wafers, the width, lengthand height of the vertical heat treatment system increase, so that thefloor area and ceiling height for the installation of the heat treatmentsystem also increase. Therefore, the production costs and maintenancecosts of the vertical heat treatment system increase, so that it isrequired to miniaturize the vertical heat treatment system.

The background of the third invention will be described below.

As one of systems for heat-treating objects to be treated, such assemiconductor wafers (which will be hereinafter referred to as wafers),in a semiconductor fabricating processes, there is a vertical heattreatment system for carrying out a batch treatment. In this system, aplurality of wafers serving as objects to be treated are held on aholder (boat) while being stacked, and this holder is carried in avertical heat treatment furnace for carrying out heat treatment, e.g.,CVD (Chemical Vapor Deposition) and oxidation.

The vertical heat treatment system has a holder mounting portion (holdersupporting mechanism, boat stage) for supporting thereon the holder. Theobjects to be treated are transferred to and held in the holder which issupported on the holder mounting portion. Thereafter, the holdermounting portion, in which the objects to be treated are held, is housedin the heat treatment chamber of the vertical heat treatment system, andthe objects to be treated are heat-treated.

When the objects to be treated are heat-treated, the positionalrelationship between the interior of the heat treatment chamber and theobjects to be treated is important. Since the temperature distributionand the concentration distribution of atmospheric gas exist in the heattreatment chamber, it is required to arrange the objects in the heattreatment chamber so that the centers of these distributions correspondsto the center of the wafers serving as the objects to be treated. If theheat treatment is carried out in a state that these centers do notcorrespond, the thickness values of the films formed on the objects areuniform.

In order to make the positional relationship between the heat treatmentchamber and the objects constant, it is effective to make the positionalrelationship between the holder and the objects constant.

There are some cases where the position shift occurs when the holder(boat) is mounted on the holder mounting portion (holder supportingmechanism, boat stage), and there is some possibility that the positionerror causes errors in the position relationship between the objects andthe holder when the objects are transferred.

The background of the fourth invention will be described below.

As one of systems for heat-treating objects to be treated, such assemiconductor wafers (which will be hereinafter referred to as“wafers”), in a semiconductor fabricating processes, there is a verticalheat treatment system for carrying out a batch treatment. In thissystem, a plurality of wafers are held on the multiple stages of aholder, such as a wafer boat, and this holder is carried in a verticalheat treatment furnace for carrying out various heat treatments, such asdiffusion, oxidation or CVD (Chemical Vapor Deposition).

In recent years, in order to surely inhibit contamination due toparticles and natural oxide films on the wafers from being produced in aregion called a loading area for carrying wafers in and out of the heattreatment furnace in such a vertical heat treatment system, a closedtype system or the like has been put to practical use wherein theloading area is separated as an airtight region which is isolated fromoutside air, to form an atmosphere of an inert gas, such as nitrogengas, to carry the wafers in and out.

By the way, the heated wafers after the heat treatment are carried inthe above described loading area from the heat treatment furnace, andthe temperature of the loading area is high, so that it is required toprovide a cooling mechanism. This cooling mechanism is provided formainly protecting a filter or the like for purifying the interior of thearea, from heat. Therefore, in view of the suppression of the flying ofparticles in the area, the cooling mechanism is provided in the vicinityof an intake hole, i.e., relatively below the loading area.

However, the above described conventional cooling mechanism has thefollowing problems. That is, in recent years, in order to furtherimprove the productivity of semiconductor devices, the size of wafersserving as objects to be treated is being changed from a diameter of 8inches (about 200 mm) to a relatively large diameter of 12 inches (about300 mm). When wafers of this large size are carried out of alarge-diameter heat treatment furnace which heat-treated the wafers, alarge amount of heat is emitted from a throat, and the temperature ofthe loading area suddenly rises due to a large amount of radiationsimultaneously emitted from the large-diameter wafers and the waferboat, so that there is a problem in that various control parts includingelectrical parts provided in the area are damaged.

Moreover, this phenomenon that the temperature in the loading areasuddenly rises to the high temperature causes a more serious problem inthe case of the closed type (inert gas purging box type) system forcirculating an inert gas in the area.

DISCLOSURE OF THE INVENTION

The first invention has been made to effectively solve the abovedescribed problems. It is an object of the first invention to provide avertical heat treatment system capable of simplifying the structure ofvarious mechanisms in the vicinity of an opening which is formed in apartition wall separating a housing-box transfer area from atreating-object transfer area (a wafer transfer area), and ofcontributing to space saving, when an object to be treated is carried inthe vertical heat treatment system through the opening to carry out apredetermined treatment.

According to the first invention, there is provided a vertical heattreatment system for carrying an object to be treated, which is housedin a treating-object housing box closed by an opening/closing lid, in atreating-object transfer area via an opening, which is formed in apartition wall separating a housing-box transfer area for transferringthe treating-object housing box from the treating-object transfer areain an atmosphere of an inert gas, to carry out a predeterminedtreatment, wherein standby box transfer means is provided in thehousing-box transfer area for holding a treating-object housing box,which houses therein the next object to be carried in thetreating-object transfer area, in the vicinity of the opening to causethe treating-object housing box to stand by.

Thus, when objects to be treated are carried out of one treating-objecthousing box into the treating-object transfer area via the opening ofthe partition wall or the like, the standby box transfer means causesthe next treating-object housing box to stand by in the vicinity of theopening (mounting table), and immediately after the objects in the lasttreating-object housing box are completely carried out, thetreating-object housing box during standby can be set in the opening tocarry objects out. Therefore, the carrying and transfer of the objectsin and to the treating-object transfer area can be quickly andefficiently carried out in a space saving state without causing thestructure to be so complicated.

In this case, for example, in the housing-box transfer area, there maybe provided a stocker portion for temporarily storing therein thetreating-object housing box, and a box transfer arm for transferring thetreating-object housing box in the stocker portion to a mounting tablewhich is provided in the opening.

In addition, an opening/closing door may be provided in the opening, andan opening/closing mechanism for removing the opening/closing door andthe opening/closing lid to cause the opening/closing door and theopening/closing lid to take shelter may be provided in thetreating-object transfer area.

The second invention has been made in view of the above describedcircumstance. It is an object of the second invention to provide avertical heat treatment system having a small influence of heat on atreating-object transfer mechanism when a holder is carried out of aheat treatment furnace.

It is another object of the second invention to provide a small verticalheat treatment system having a high throughput.

It is a further object of the second invention to provide a controlmethod capable of stably operating such a vertical heat treatmentsystem.

According to the second invention, a vertical heat treatment systemcomprises: a lifting mechanism which is vertically moved for carrying aholder, in which an object to be treated is held, in and out of a heattreatment furnace; a holder mounting portion for mounting thereon theholder to transfer the object; a holder transfer mechanism fortransferring the holder between the lifting mechanism and the holdermounting portion; and a treating-object transfer mechanism fortransferring the object to the holder which is supported on the holdertransferring portion, the treating-object transfer mechanism having amotion space region which overlaps with a motion space region of theholder transfer mechanism, wherein the treating-object transfermechanism comprises a swivel arm supported so as to be rotatable about avertically extending rotation center shaft, and a transfer head providedon the tip portion of the swivel arm so as to be rotatable on ahorizontal plane, and further comprises driving means having thesheltering function of moving the transfer head of the treating-objecttransfer mechanism on the horizontal plane along the outer peripheraledge of the lifting mechanism, which is positioned at a lower position,to cause the transfer head to take shelter on a side face portion of ahousing.

In the vertical heat treatment system according to the second invention,the sheltering function of the driving means of the treating-objecttransfer mechanism preferably causes the transfer head of thetreating-object transfer mechanism to revolve around the rotation centershaft of the swivel arm while causing the transfer head itself to rotateon its axis in the opposite direction to the direction of rotation ofthe transfer head, to cause the transfer head to take shelter on theside face portion in the housing.

In addition, in the vertical heat treatment system according to thesecond invention, the sheltering function of the driving means of thetreating-object transfer mechanism preferably operates the transfer headof the treating-object transfer mechanism from a state that the transferhead is positioned at a reference position in its motion space region.

Moreover, in the vertical heat treatment system according to the secondinvention, the driving means of the treating-object transfer mechanismpreferably comprises a stretching mechanism for rotating the swivel arm,and a belt transmission mechanism for transmitting the rotational motionof the swivel arm to the transfer head. In this case, the referenceposition in the motion space region may be set by a pulley ratio in thebelt transmission mechanism.

According to the second invention, there is provided a method forcontrolling a vertical heat treatment system comprising: a liftingmechanism which is vertically moved for carrying a holder, in which anobject to be treated is held, in and out of a heat treatment furnace; aholder mounting portion for mounting thereon the holder to transfer theobject; a holder transfer mechanism for transferring the holder betweenthe lifting mechanism and the holder mounting portion; and atreating-object transfer mechanism for transferring the object to theholder which is supported on the holder transferring portion, thetreating-object transfer mechanism having a motion space region whichoverlaps with a motion space region of the holder transfer mechanism,the treating-object transfer mechanism comprising a swivel arm supportedso as to be rotatable about a vertically extending rotation centershaft, and a transfer head provided on the tip portion of the swivel armso as to be rotatable on a horizontal plane, wherein the transfer headof the treating-object transfer mechanism is moved on the horizontalplane along the outer peripheral edge of the lifting mechanism, which ispositioned at a lower position, to take shelter on a side face portionof a housing, when the holder transfer mechanism is operated.

In the control method according to the second invention, the transferhead of the treating-object transfer mechanism may be caused to revolvearound the rotation center shaft of the swivel arm while the transferhead itself is caused to rotate on its axis in the opposite direction tothe direction of rotation of the transfer head, to take shelter on theside face portion in the housing.

According to the vertical heat treatment system of the second invention,when the holder is transferred, the treating-object transfer mechanismtakes shelter on one side face portion of the housing, so that theholder during transfer does not interfere with the treating-objecttransfer mechanism. In addition, the treating-object transfer mechanismtakes shelter on the same plane as that of the lifting mechanism whichis positioned at the lower position, so that the influence of heat fromthe heat treatment furnace and so forth can be very small.

In addition, since the space required for the sheltered operation can bereduced by allowing the transfer head of the treating-object transfermechanism to move along the outer peripheral edge of the liftingmechanism, the holder mounting portion and so forth can be arranged at ahigh spatial utilization factor, so that the whole system can beminiaturized while maintaining a high throughput.

According to the control method of the invention, it is possible tosurely prevent the holder during transfer from interfering with thetreating-object transfer mechanism, and the influence of heat from theheat treatment furnace and so forth can be very small, so that it ispossible to stably operate the vertical heat treatment system.

In addition, since the transfer head of the treating-object transfermechanism can take shelter in a relatively small space, the holdermounting portion and so forth can be arranged at a high spatialutilization factor, and the whole system can be miniaturized whilemaintaining a high throughput.

In view of the foregoing, it is an object of the third invention toprovide a heat treatment system having a holder supporting mechanismcapable of mounting an object to be treated at a predetermined position.

In order to accomplish the above described object, a vertical heattreatment system according to the third invention has a holdersupporting mechanism comprising: a holder mounting table for mountingthereon a holder for holding a plurality of objects to be heat-treated,in a stacked state; and a holder position adjusting mechanism includinga plurality of protruding portions corresponding to the shape of abottom plate of the holder, and a distance varying mechanism for varyingthe distance between the plurality of protruding portions.

Since the holder supporting mechanism has the holder position adjustingmechanism for adjusting the position of the holder, the positioning ofthe holder can be easily carried out after the holder is mounted on theholder mounting table. As a result, it is possible to precisely transferthe objects to the holder. Furthermore, this positioning can be carriedout by changing the distance between the plurality of protrudingportions corresponding to the shape of the bottom plate of the holder.

The holder supporting mechanism may further comprise a sliding mechanismfor allowing the holder mounting table to move on a plane along a holdermounting surface of the holder mounting table. By the sliding mechanism,the holder mounting table can easily move with the holder mountingtable, and the positioning of the holder can be easily carried out.

The holder supporting mechanism may further comprise a returningmechanism for returning the holder mounting table to a predeterminedposition, the returning mechanism including biasing means for biasingthe holder mounting table in a different direction on a plane along aholder mounting surface of the holder mounting table.

Thus, it is possible to return the position of the holder mounting tablebefore the transfer of the holder, and it is possible to ensure themovable range of the holder mounting table during the positioning of theholder.

According to the third invention, there is provided a method fortransferring an object to be treated, the method comprising: a mountingstep of causing a holder, which serves to hold a plurality of objects tobe heat-treated in a stacked state, to be mounted on a holder mountingtable; a positioning step of moving the holder, which is mounted on theholder mounting table at the mounting step, together with the holdermounting table, on a plane along a holder mounting surface of the holdermounting table to position the holder at a predetermined position; atransfer step of transferring the objects to the holder which ispositioned at the positioning step; and a returning step of removing theholder, to which the objects are transferred at the transfer step, fromthe holder mounting table to return the holder mounting table to apredetermined position.

Since the position of the holder is adjusted before the objects aretransferred, the precision of the position is improved when the objectsare transferred to the holder. In addition, since the position of theholder mounting table is returned after removing the holder to which theobjects are transferred, it is easy to ensure the precision ofadjustment of the position of the holder.

The fourth invention has been made to solve the above describedproblems. It is an object of the fourth invention to provide a heattreatment system having excellent cooling effects in a carrying-in/outregion of a heat treatment furnace in and out of which an object to betreated is carried.

It is another object of the fourth invention to provide a heat treatmentsystem having excellent cooling effects while inhibiting thecarrying-in/out region from being contaminated by particles.

In order to accomplish the above described objects, according to thefourth invention, a heat treatment system comprises: a heat treatmentfurnace for heat-treating an object to be treated; a throat which isprovided in the heat treatment furnace for carrying the object in andout; and a cooling mechanism for cooling the vicinity of the throat.

Since the heat treatment system according to the fourth invention coolsthe vicinity of the throat of the heat treatment furnace, heat emittedfrom the throat of the heat treatment furnace and be removed and theheated objects can be cooled, when the objects heated to a hightemperature in the heat treatment furnace are, for example, carried out.Thus, it is not feared that the temperature in the carrying-in/outregion carrying the objects in and out of the heat treatment furnace maysuddenly rise, so that it is possible to inhibit control parts and soforth provided in the carrying-in/out region from being damaged by heat.

In the heat treatment system according to the fourth invention, thecooling mechanism may comprise a ventilating unit having a ventilatingport for sending a cooling fluid toward the vicinity of the throat, anda heat exchanger arranged so as to face the ventilating port in thevicinity of the throat.

This heat treatment system according to the fourth invention caneffectively heat, which is emitted from the throat of the heat treatmentfurnace, by the ventilating unit for sending the cooling fluid to theobjects, which are carried out while being heated, and by the heatexchanger, such as a radiator, for removing heat of thetemperature-raised cooling fluid in the vicinity of the throat.

Moreover, in the heat treatment system according to the fourthinvention, the cooling mechanism may further comprise an intake fan forsucking the cooling fluid in the vicinity of the throat over the heatexchanger.

The heat treatment system according to this invention can positivelydraw the temperature-raised cooling fluid in the vicinity of the throatinto the heat exchanger by the intake fan to effectively remove theheat. Moreover, in the heat treatment system according to thisinvention, the intake fan is arranged downstream of the heat exchangerin the flow of the cooling fluid, so that the cooling fluid passingthrough the heat exchanger to be cooled is sucked by the intake fun.Thus, it is possible to inhibit the intake fun from being damaged byheat.

Moreover, in the heat treatment system according to the fourthinvention, the cooling mechanism may further comprise: a duct forforming a circulating path for the cooling fluid between the intake funand the ventilating unit so that the cooling fluid sucked by the intakefan returns to the ventilating unit; a filter, provided in the duct orthe ventilating unit, for purifying the cooling fluid which is sent bythe ventilating unit; and an intake port which is formed on the duct atleast upstream of the filter so that the cooling fluid sent by theventilating unit is sucked at a different position from a position atwhich the cooling fluid is sucked by the intake fun.

This heat treatment system according to the fourth invention can be usedfor purifying and circulating the cooling fluid for cooling the vicinityof the throat, so that this heat treatment system can be used as aclosed type system for blocking the carrying-in/out region carrying theobjects in and out of the heat treatment furnace from outside air andfor circulating the cooling fluid in this region. In addition, the heattreatment system according to this invention suitably selects the intakeport, in which the cooling fluid is sucked at a different position froma position at which the cooling fluid is sucked by the intake fun, at aposition upstream of the filter on the duct, so that the heat treatmentsystem can have excellent cooling effects while inhibiting particlesfrom flying in the carrying-in/out region.

In the heat treatment system according to the fourth invention, thecooling mechanism may further comprise a second heat exchanger which isarranged in the duct between the intake port and the filter so as tocool the cooling fluid which is drawn into the duct from the intake fanand the intake port to join.

According to the heat treatment system of the fourth invention, thefilter is arranged downstream of the second heat exchanger in the flowof the cooling fluid, so that the cooling fluid passing through thesecond heat exchanger to be cooled further passes through the filter.Thus, it is possible to inhibit the filter from being damaged by heat.

According to the fourth invention, there is provided a heat treatmentsystem having a loading chamber in which a mechanism for carrying anobject to be treated in and out of a throat of a bottom portion of aheat treatment furnace and which has a loading chamber separated as anairtight region, wherein the throat of the bottom portion of the heattreatment furnace is arranged above the loading chamber, the loadingchamber including: a ventilating unit which has a ventilating port inthe vicinity of the throat and a filter for purifying and sending acooling fluid from the ventilating port to the vicinity of the throatfrom the side; a first heat exchanger which is arranged so as to facethe ventilating port in the vicinity of the throat; an intake fan forsucking the cooling fluid in the vicinity of the throat over the firstheat exchanger; a circulating duct which forms a circulating path forthe cooling fluid between the intake fan and the ventilating unit sothat the cooling fluid sucked by the intake fan returns to theventilating unit, at least a part of sand circulating duct beingarranged below the loading chamber; an intake port which is formed inthe part of the circulating duct below the loading chamber so that apart of the cooling fluid sent by the ventilating unit is sucked belowthe loading chamber; and a second heat exchanger which is arranged inthe circulating duct between the intake port and the filter so that thecooling fluid drawn into the circulating duct from the intake fan andthe intake port to join is cooled.

This heat treatment system according to the fourth invention can be usedfor purifying and circulating the cooling fluid for cooling the vicinityof the throat, so that this heat treatment system can be used as aclosed type system for blocking the carrying-in/out region for carryingthe objects in and out of the heat treatment furnace from outside airand for circulating the cooling fluid in this region. In addition, inthe heat treatment system according to this invention, above the loadingchamber, the flow of the cooling fluid is regulated by the intake funand the duct, and the other intake port for the cooling fluid isprovided below the loading chamber to similarly regulate the flow of thecooling fluid, so that the heat treatment system can have excellentcooling effects while inhibiting particles from flying in thecarrying-in/out region.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic diagram of a vertical heat treatment systemaccording to the first invention;

FIG. 2 is an enlarged plan view of a standby box transfer means shown inFIG. 1;

FIG. 3 is a top view of the standby box transfer means;

FIG. 4 is an illustration for explaining the operation of the standbybox transfer means;

FIG. 5 is a perspective view of a treating-object housing box;

FIG. 6 is a perspective view showing the state that the lid of thetreating-object housing box is open;

FIG. 7 is a view showing a locking mechanism for the lid;

FIG. 8 is an enlarged view showing a principal part of an example of aconventional system;

FIG. 9 is an enlarged view showing a principal part of an example ofanother conventional system;

FIG. 10 is a perspective view showing an example of a schematicconstruction of a heat treatment system according to the secondinvention;

FIG. 11 is a plan view of a loading area of the heat treatment systemshown in FIG. 10;

FIG. 12 is an illustration schematically showing an example of aconstruction of a driving means of a wafer transfer mechanism;

FIG. 13 is an illustration showing the state that the wafer transfermechanism is positioned at (a) a sheltered motion starting position and(b) a sheltered position;

FIG. 14 is an illustration showing the locus of a base when the wafertransfer mechanism takes shelter;

FIG. 15 is a perspective view showing the whole construction of a heattreatment system according to the third invention;

FIG. 16 is a partially sectional view of a first holder mounting portion(boat stage) shown in FIG. 15, which is viewed from the top;

FIG. 17 is a partially sectional view of the first holder mountingportion taken along line A-B of FIG. 15;

FIG. 18 is a partially sectional view of the first holder mountingportion taken along line C-D of FIG. 15;

FIG. 19 is a side view of the first holder mounting portion viewed inthe direction of arrow E of FIG. 15;

FIG. 20 is a side view of the first holder mounting portion viewed inthe direction of arrow F of FIG. 15;

FIG. 21 is a conceptual view showing the construction of the firstholder mounting portion;

FIG. 22 is a schematic diagram showing the first holder mounting portionbefore a holder is mounted thereon;

FIG. 23 is schematic diagram showing the first holder mounting portionwhen the holder is mounted thereon;

FIG. 24 is a schematic diagram showing the first holder mounting portionwhen the position of the holder is adjusted;

FIG. 25 is a schematic diagram showing the first holder mounting portionwhen it is fixed and when the holder to which wafers are transferred ismounted thereon;

FIG. 26 is a schematic diagram showing the first holder mounting portionwhen the holder is removed;

FIG. 27 is a schematic diagram showing the first holder mounting portionwhen the position of a holder mounting table returns;

FIG. 28 is a flow chart showing the procedure for transferring an objectto be treated, to the holder on the first holder transferring portion;

FIG. 29 is a perspective view showing a preferred embodiment of avertical heat treatment system according to the fourth invention;

FIG. 30 is a perspective view showing the vertical heat treatment systemof FIG. 29 viewed from a different angle;

FIG. 31 is a perspective view showing the construction of a gascirculating cooling mechanism of the vertical heat treatment system ofFIG. 29, viewed from the back side of the system body;

FIG. 32 is a view of the vertical heat treatment system of FIG. 29,viewed from the back face;

FIG. 33 is a view showing a safety mechanism of the vertical heattreatment system of FIG. 29;

FIG. 34 is a sectional view of top and bottom radiators constituting thegas circulating cooling mechanism of FIG. 31, viewed from the side of asurface facing FFU; and

FIG. 35 is a view schematically showing the flow of nitrogen gas by thegas circulating cooling mechanism of FIG. 31.

BEST MODE FOR CARRYING OUT THE INVENTION

Referring to the accompanying drawings, a preferred embodiment of avertical heat treatment system according to the first invention will bedescribed below in detail.

FIG. 1 is a schematic diagram of a vertical heat treatment systemaccording to the first invention, FIG. 2 is an enlarged view of astandby box transfer means shown in FIG. 1, FIG. 3 is a top view of thestandby box transfer means, and FIG. 4 is an illustration for explainingthe operation of the standby box transfer means. Furthermore, the samereference numbers are given to the same components as those of the abovedescribed conventional system.

First, as shown in FIG. 1, the whole vertical heat treatment system 40is surrounded by a housing 42 of stainless or the like, and the interiorthereof is divided by a partition wall 26 into two parts of ahousing-box transfer area 44 for transferring a treating-object housingbox 2 (which will be also hereinafter referred to as a housing box) anda wafer transfer area 46 serving as a treating-object transfer area fortransferring a semiconductor wafer W which is an object to be treated.Clean air flows in the box transfer area 44, and the interior of thewafer transfer area 46 is in an atmosphere of an inert gas of N₂ gas orthe like. The treating system 40 mainly comprises: a carrying-in/outport 48 for mainly carrying the housing box 2 in and out of the system40; a stocker portion 50 for temporarily storing the housing box 2; atransfer stage 54 for transferring a semiconductor wafer W between thehousing box 2 and a treating-object boat 52; a treatment unit 56 forcarrying out a predetermined treatment with respect to the semiconductorwafer W which is transferred to the treating-object boat 52 to be heldthereon; a lid opening/closing mechanism 58 which is provided in thevicinity of the carrying-in/out port 48; an opening/closing mechanism 34which is provided inside of the wafer transfer area 46 for the transferstage 54; and a standby box transfer means 60 which is a feature of thepresent invention and which is provided inside of the housing-boxtransfer area 44 for the transfer stage 54.

In the above described carrying-in/out port 48, the housing 42 is formedwith a box carrying-in/out opening 62 which is always open. Outside ofthe box carrying-in/out opening 62, there is provided an outsidemounting table 64 for supporting thereon the housing box 2 which istransferred from the outside. Inside, of the box carrying-in/out opening62, there is provided an inside mounting table 66 for supporting thereonthe housing box 2 which slides and moves from the outside mounting table64. On the top of the outside or inside mounting table 64 or 66, thereis provided a sliding plate 68 capable of sliding and moving betweenboth of the mounting tables 64 and 66. The sliding plate 68 is capableof moving while the housing box 2 is supported thereon. Between theinside mounting table 66 and a portion right below the boxcarrying-in/out opening 62 inside of the box carrying-in/out opening 62,the lid opening/closing mechanism 58 capable of vertically moving(rising and setting) is provided for temporarily opening and closing anopening/closing lid 10 of the housing box 2. The reason why theopening/closing lid 10 of the housing box 2 is temporarily taken is thatwafer information, such as the number, positions and states of wafers inthe housing box 2, is intended to be detected by a sensor (not shown).

On the lid opening/closing mechanism 58, there is mounted a pair of keyportions 70 (only one is shown in FIG. 1) which are capable ofprotruding and retracting in horizontal directions and of rotating innormal and reverse directions. By rotating the key portions 70 in normaland reverse directions while the key portions 70 are inserted into keygrooves 16 which are shown in FIGS. 5 through 7, a locking mechanism 12can be locked and unlocked to hold it.

On the other hand, in the upper portion in the housing-box transfer area44, the above described stocker portion 50 is arranged. The stockerportion 50 is provided with two columns x two stages of shelves 71 inparallel for temporarily supporting and storing the housing box 2thereon in the shown embodiment. Furthermore, the number of the shelves71 should not be particularly limited. In fact, a large number ofshelves are provided.

Between the two shelves 71, an elevator 72 is provided so as to beraised. The elevator 72 is provided with a box transfer arm 74 whichextends in horizontal directions and which is capable of swiveling andbending and stretching. Therefore, by causing the box transfer arm 74 tobend and stretch and to move in vertical directions, the housing box 2can be held by the box transfer arm 74 to be transferred between theinside mounting table 66 and the stocker portion 50.

In the above described transfer stage 54, a single opening 28substantially having the same size as that of the opening 4 (see FIG. 6)of the housing box 2 is formed in the partition wall 26 for separatingboth of the areas 44 and 46 from each other, and a single mounting table30 is horizontally provided on the side of the housing-box transfer area44 of the opening 28, so that the housing box 2 can be mounted thereon.On one side of the mounting table 30, a horizontal actuator 76 forpressingly biasing the housing box 2, which is mounted thereon, towardthe partition wall 26 is provided so that the opening edge of theopening portion 4 of the box vessel 6 substantially airtightly contactsthe opening edge of the opening 28 of the partition wall 26 while theopening/closing lid 10 of the housing box 2 faces the opening 28. Theopening 28 is provided with an opening/closing door 32 for opening andclosing the opening 28. In the housing-box transfer area 44, the standbybox transfer means 60 is provided for causing the housing box 2 to standby in the vicinity of the opening 28. The construction of the transfermeans 60 will be described later.

Right below the opening 28 inside of the wafer transfer area 46, theopening/closing mechanism 34 is provided for opening and closing theopening/closing lid 10 of the housing box 2 and the opening/closing door32. As this opening/closing mechanism 34, the above describedopening/closing mechanism disclosed in Japanese Patent Laid-Open No.8-279546, or the opening/closing mechanism disclosed in Japanese PatentLaid-Open No. 11-274267 may be used.

In the wafer transfer area 46, two boat mounting tables 78 (only one isshown in FIG. 1) are provided for supporting thereon the treating-objectboat 52 such as a wafer boat. Between the boat mounting tables 78 andthe above described transfer stage 54, a wafer transfer arm 80 capableof swiveling and bending and stretching is provided. This wafer transferarm 80 is capable of being vertically moved by the elevator 82.Therefore, by causing the wafer transfer arm 80 to stretch, swivel andvertically move, the wafer W can be transferred between the housing box2 on the mounting table 30 and the treating-object boat 52 on the boatmounting table 78.

The treating-object boat 52 is made of, e.g., quartz, and capable ofsupporting, e.g., about 50 to 150 wafers W, on multiple stages at apredetermined pitch.

Above one side of the wafer transfer area 46, there is arranged atreatment unit 56 comprising a vertical heat treatment furnace having acylindrical treatment vessel 84 of quartz for carrying out apredetermined heat treatment, such as deposition, oxidation ordiffusion, with respect to the large number of wafers W at a time. Belowthe treatment vessel 84, there is arranged a cap 88 capable of beingvertically moved by the elevator 86. By mounting the treating-objectboat 52 on the cap 88 to move the cap 88 upwards, the boat 52 can beloaded in the treatment vessel 84 via the bottom end opening of thetreatment vessel 84. At this time, the bottom end opening of thetreatment vessel 84 is airtightly closed by the cap 88. Between thelowered cap 88 and the above described boat mounting table 87, there isprovided a boat transfer arm 90 capable of bending and stretching andswiveling, so that the treating-object boat 52 can be transferredbetween the boat mounting table 78 and the cap 88.

On the housing ceiling portion above the above described treatment unit56, there is provided a ceiling ventilating plate having a ventilatinghole, such as a punching metal, for introducing outside clean area intothe treatment unit 56. Above the transfer stage 54 and on the side ofthe back face of the stocker 50, a ventilating partition wall 94 havinga ventilating hole is provided. On the ventilating partition wall 94 onthe side of the treatment unit 56, a filter member 96 of, e.g., a HEPAfilter, and a fan 98 are provided. For example, by passing clean air(gas)) introduced from the outside through the filter member 96, cleanair having a high cleanliness factor is introduced into the housing-boxtransfer area 44.

Also as shown in FIGS. 2 and 3, the standby box transfer means 60 whichis a feature of the present invention has a lifting table 102 engagedwith two guide rails 100 which are provided in parallel in the heightdirection of the side wall 42A of the housing 42. The lifting table 102is capable of being vertically moved by a required predetermined strokeby a lifting means, e.g., a driving ball screw, which passes through thelifting table 102 and which is screwed thereto. Furthermore, the ballscrew 104 is capable of being normally and reversely rotated by adriving motor (not shown).

The lifting table 102 is provided with an arm portion 106 which extendsin horizontal directions and which is capable of bending and swiveling.The arm portion 106 comprises a first arm 106A, the base end portion ofwhich is pivotably mounted on the side of the lifting table 102, and asecond arm 106B which is pivotably mounted on the tip portion of thefirst arm 106A. The second arm 106B is set so as to be always directedin the same direction regardless of the turning angle of the first arm106A. On the tip of the second arm 106B, a box gripping portion 108 isprovided. On the bottom portion of the box gripping portion 108, thereare provided a pair of claw portions 110 which are slidable inhorizontal directions so as to approach or leave each other. The topgripping handle 24 of the housing box 2 can be gripped by the clawportions 110 to be transferred. Furthermore, the construction of thestandby box transfer means 60 should not be limited to the abovedescribed construction if it can grip and transfer the housing box 2 asdescribed above.

The operation of the treatment system 40 with the above describedconstruction will be described below.

First, the interior of the wafer transfer area 46 is in an atmosphere ofan inert gas, e.g., N₂ gas, in order to prevent natural oxide films fromadhering to the surface of the wafers. The interior of the housing-boxtransfer area 44 is maintained in an atmosphere of clean air.Specifically, clean air is introduced from the ceiling ventilating plate92 of the housing 42 into the box transfer area 44 via the filter member96 and the ventilating partition wall 94, and circulates in the area 44to be exhausted from its bottom.

First the whole flow of the semiconductor wafers W will be described.The housing box 2 transferred from the outside is mounted on the outsidemounting table 64 so that the opening/closing lid 10 faces the boxcarrying-in/out opening 62. Then, by driving the lid opening/closingmechanism 58, the opening/closing lid 10 of the housing box 2 istemporarily removed, and the number and positions of the wafers housedin the housing box 2 are detected by a sensor (not shown). If thisdetection is completed, the lid opening/closing mechanism 58 is drivenagain, so that the removed opening/closing lid 10 is mounted on thehousing box again.

Then, if the sliding plate 68 on the outside mounting table 64, on whichthe housing box 2 is supported, is moved forwards, the sliding plate 68is transferred to the inside mounting table 66. Then, by driving the boxtransfer arm 74, the housing box 2 supported on the inside mountingtable 66 is taken to be held. Moreover, by driving the elevator 72, thehousing box 2 is transfer to a predetermined position on the shelf 71 ofthe stocker portion 50 and temporarily stored thereon. Simultaneously,the housing box 2 which is temporarily stored on the shelf 71 and whichhouses therein the wafer serving as an object to be treated is taken bythe box transfer arm 74, and the elevator 72 is driven to move itdownwards as described above. If the mounting table 30 of the transferstage 54 is empty, the housing box 2 is transferred to the mountingtable 30 of the transfer stage 54.

On the other hand, if another housing box 2 has been set on the mountingtable 30, the housing box 2 on the box transfer arm 74 is gripped by thestandby box transfer means, which is a feature of the present invention,to be transferred to the vicinity of the opening 28 to stand by. Theopening/closing lid 10 of the housing box 2 on the mounting table 30 isdirected to the opening/closing door 32 which is provided in thepartition wall 26, and the housing box 2 is pressingly biased to befixed on the mounting table 30 by means of a horizontal actuator whichis provided on one side of the mounting table 30.

By driving the opening/closing mechanism 34 in this state, theopening/closing door 32 of the opening 28 and the opening/closing lid 10of the housing box 2 are removed to take shelter upwards or downwards.Since the peripheral edge portion of the opening portion of the housingbox 2 is pressed against the partition wall 26 to be in a tight contactstate, gases do not flow between both of the areas 44 and 46 via theopening 28. Then, by driving the wafer transfer arm 80 and the elevator82, the wafers W housed in the housing box 2 are taken out, one or aplurality of wafers at a time, to be mounted on the treating-object boat52 which is provided on the boat mounting table 78. If the transfer ofthe wafers W to the treating-object boat 52 is completed, the boattransfer arm 90 is driven, so that the treating-object boat 52 on theboat mounting table 78 is mounted on the cap 88 which has been moved tothe lowermost end. Then, if the transfer of the treating-object boat 52is completed, the elevator 86 is driven to upwardly move the cap 88which has been mounted on the treating-object boat 52, so that the boat52 is introduced into the treatment vessel 84 via the bottom end openingof the treatment vessel 84 of the treatment unit 56 to be loadedtherein. Then, the bottom end opening of the treatment vessel 84 isclosed by the cap 88. In this state, a predetermined heat treatment,e.g., deposition, oxidation or diffusion, is carried out with respect tothe wafers W in the treatment unit 56.

If the predetermined heat treatment is thus completed, the reverseoperation of the above described operation is carried out to take outthe treated wafer W. That is, the treating-object boat 52 is moveddownwards from the interior of the treatment vessel 84 to be unloaded tobe mounted on the boat mounting table 78. Then, the treated wafer W istransferred by the wafer transfer arm 80 from the boat 52 into thehousing box 2. The transfer of the treated wafer W into the housing box2 is completed, the opening/closing mechanism 34 is driven to mount theopening/closing lid 10, which has been held by the opening/closingmechanism 34, and the opening/closing door 32 in the housing box 2 andthe opening 28, respectively.

Then, the box transfer arm 74 is driven to temporarily store the housingbox 2 in the stocker portion 50 or to transfer the housing box 2 to theoutside of the treatment system 40 via the box carrying-in/out opening62 without storing the housing box 2. While the box transfer arm 74 istransferring the housing box 2 in which the treated wafer is housed, thestandby box transfer means 60 which has gripped an empty housing box tostand by is set the empty housing box on the mounting table 30, and thehousing of the treated wafer into the housing box is started.Subsequently, the same operation is repeated. Furthermore, the abovedescribed flow of the housing box 2 is only shown as an example. Ofcourse, the invention should not be limited thereto.

Referring to FIG. 4, the operation of the above described standby boxtransfer means 60 will be described below in detail.

First, in FIG. 4(A), one housing box 2A has been mounted on the mountingtable 30, and the opening/closing door 32 for closing theopening/closing lid 10 and the opening 28 has been removed by theopening/closing mechanism 34 to be moved downwards. In addition, thesemiconductor wafer W in the housing box 2A has been carried out. Thus,while the wafer in the housing box 2A is being carried out, the boxtransfer arm 74 in the empty state takes the housing box 213, in which awafer to be treated next is housed, out of the stocker portion 50. Then,as shown in FIG. 2, the standby box transfer means 60 rotates the armportion 106 and drives the box gripping portion 108 to receive thehousing box 2B from the box transfer arm 74 to cause the housing box 2Bto stand by in the vicinity of (in FIG. 4(A), slightly above) thehousing box 2A on the mounting table 30.

Thus, if the carrying-out of the wafer W in one housing box 2A iscompleted, the opening/closing mechanism 34 is driven to mount theopening/closing lid 10 and the opening/closing door 32. Then, thesliding plate 30A on the mounting table 30 is slightly moved backwardsto interrupt the interference of the housing box 2A with the opening 28,and the emptied housing box 2A is picked up from the top of the mountingtable 30 to be transferred by means of the box transfer arm 74.

Thus, the top of the mounting table 30 is emptied, the standby boxtransfer means 60 is driven to move the arm portion 106 downwards, sothat the other housing box 2B which has stood by slightly above themounting table 30 is set on the mounting table 30 as shown in FIG. 4(B).At this time, the pair of claw portions 110 of the box gripping portion108 are caused to slide so as to leave each other, so that the grippinghandle 24 of the housing box 2B can be removed. Then, the housing box 2Bwhich has been newly set on the mounting table 30 is fixed, and thesliding plate 30A is advanced toward the opening 28, so that the tip ofthe housing box 2B contacts the opening 28.

Then, as shown in FIG. 4(C), both of the opening/closing lid 10 of thehousing box 2B and the opening/closing door 32 of the opening 28 areremoved by the opening/closing mechanism 34 as described in FIG. 4(A),and the wafer in the housing box 2B is carried out.

Then, while the wafer is carried out, the housing box 2C in which awafer to treated next is housed is transferred above in the same manneras the above described manner to be caused to stand by therein.Subsequently, the above described operations are similarly repeated.

On the other hand, when the treated semiconductor wafer is introducedinto an empty housing box, the reverse operation of the above describedoperation is carried out. Also in that case, the standby box transfermeans 60 may be used for causing an empty housing box to stand byslightly above the mounting table 30.

Thus, according to this preferred embodiment, the standby box transfermeans 60 is used for causing a housing box, in which a wafer to betreated next is housed, to stand by in the vicinity of the mountingtable 30, or for causing an empty housing box, in which a wafer is to behoused next, to stand by. Therefore, immediately after the operation forcarrying a wafer in and out of the last housing box is completed, theoperation for carrying a wafer in and out of a housing box duringstandby, so that it is possible to rapidly and efficiently carry out thecarrying-in/out operation.

In addition, the structure of the standby box transfer means 60 isrelatively simple, and it is sufficient if only one opening/closingmechanism 34 is provided, so that the costs can be smaller than those inconventional systems. In addition, since it is sufficient if only onemounting table 30 is provided, it is possible to greatly reduce theoccupied space.

While the housing box 2 has been caused to stand by slightly above themounting table 30, this standby position should not particularly belimited if it is in the vicinity of the mounting table 30. For example,the housing box may be caused to stand by in a substantially lateraldirection of the mounting table 30.

While the semiconductor wafer has been described as an example of anobject to be treated, the present invention should not be limitedthereto, but the invention may be applied to a glass substrate or an LCDsubstrate.

As described above, according to the vertical heat treatment system ofthe first invention, excellent effects can be provided as follows.

According to the first invention, when an object to be treated iscarried out of one treating-object housing box to be carried in thetreating-object transfer area via the opening of the partition wall, thestandby box transfer means is used for causing the nest treating-objecthousing box to stand by in the vicinity of the opening (mounting table).Then, when the carrying-out of the object in the last treating-objecthousing box is completed, the treating-object housing box during standbycan be immediately set in the above described opening to carry theobject out. Therefore, the carrying and transfer of the object in and tothe treating-object transfer area can be quickly and efficiently carriedout in a space saving state without causing the structure to be socomplicated.

Also when the treated object is transferred, the carrying-in/out of theobject can be quickly and efficiently carried out in the same manner asthe above described manner by causing an empty treating-object housingbox to stand by in the vicinity of the mounting table.

Referring to the accompanying drawings, the second invention will bedescribed below in detail.

FIG. 10 is a perspective view showing an example of a schematicconstruction of a vertical heat treatment system according to the secondpreferred embodiment, and FIG. 11 is a plan view of a loading area ofthe vertical heat treatment system shown in FIG. 10.

This heat treatment system 1010 is separated into front and rearportions by a partition wall 1012, and has a housing. 1011 which forms acarrier transfer area Sa in which a carrier (cassette) housing therein asemiconductor wafer serving as an object to be treated is carried in andout and stored, and a loading area Sb in which the semiconductor waferis transferred and heat-treated. In the front face of the housing 1011,a carrying-in/out opening 1013 for carrying a carrier 1020 in and out isformed, and a carrying-in/out stage 1014 serving as an inlet/outlet portto the carrying-in/out opening 1013 is provided. The carrier transferarea Sa is maintained in an atmosphere of atmospheric air, and theloading area Sb is maintained in an atmosphere of atmospheric air or anatmosphere of an inert gas, such as nitrogen gas. In FIG. 10, referencenumber 1015 denotes a sensor mechanism for opening a lid 1020A of thecarrier 1020 to detect the position and number of semiconductor wafers,reference number 1016 denotes a shelf-like carrier storage portion forstoring a plurality of carriers 1020, and reference number 1017 denotesa notch aligning mechanism for aligning notches (cut-out portions),which are formed in the peripheral edge portions of the semiconductorwafers, in one direction in order to arrange crystal orientation.

The carrier 1020 comprises a plastic vessel capable of housing therein aplurality of, e.g., about 13 to 25, semiconductor wafers having apredetermined diameter, e.g., a diameter of 300 mm, on multiple stagesin a horizontal state at regular intervals in vertical directions. Thecarrier 1020 is detachably provided with a lid 1020A for airtightlyclosing a wafer outlet (not shown) which is formed in the back facethereof.

In the carrier transfer area Sa, carrier mounting portions 1021 areprovided in the vicinity of the partition wall 1012 for supportingthereon the carrier 1020. In order to improve throughput, the pluralityof, e.g., two, carrier mounting portions 1021 are provided so as to bearranged in vertical directions although only one carrier mountingportion is shown for convenience. Thus, while the semiconductor wafersare being transferred in one carrier mounting portion, the carrier 1020can be exchanged in the other carrier mounting portion.

In the carrier transfer area Sa, there is provided a carrier transfermechanism 1025 for transferring the carrier 1020 between the carrierstorage portions 1016, 1016 and the carrier mounting portion 1021.

The carrier transfer mechanism 1025 comprises: a lifting guide 1025Awhich is provided on one side of the housing 1011; a lifting arm 1025Bwhich is vertically moved by the lifting guide 1025A; and a transfer arm1025C which is provided on the lifting arm 1025B so as to be rotatableon the horizontal plane. As shown in FIG. 11, the transfer arm 1026Ccomprises a first arm 1251, and a second arm 1252 which is provided onthe tip portion of the first arm 1251 so as to be rotatable on thehorizontal plane.

The partition wall 1012 has an opening portion 1022, which is arrangedso as to correspond to the height of each of the carrier mountingportions 1021, for establishing a communication between the carriertransfer area Sa and the loading area Sb. The opening portion 1022substantially has the same diameter as that of the wafer outlet of thecarrier 1020.

The partition wall 1012 is provided with a door (1023 in FIG. 11) forclosing the opening portion 1022 from the side of the loading area Sb.This door 1023 is open and closed by a door opening/closing mechanism(not shown) which is provided in the loading area Sb.

There is provided a lid opening/closing mechanism (not shown) foropening and closing the lid 1020A of the carrier 1020. By thismechanism, the door 1020A and the lid 1020A of the carrier 1020 aremoved to the loading area Sb and caused to take shelter upwards ordownwards so as not to prevent the semiconductor wafers from beingtransferred.

In the rear portion (lower portion in FIG. 11) of the loading area Sb, aheat treatment furnace 1028 is provided in the upper portion, and a boatelevator mechanism 1030 serving as a lifting mechanism which is moved invertical directions for carrying wafer boats 1031A and 1031B of, e.g.,quartz, each of which is a holder for holding a plurality of, e.g.,about 50 to 150, semiconductor wafers on multiple stages at regularintervals in vertical directions, in and out of the heat treatmentfurnace 1028 is provided so as to face the carrier mounting portion1021.

The boat elevator mechanism 1030 comprises a lifting guide 1032A, and amounting table 1032B on which the wafer boats 1031A and 1031B aresupported and which is vertically moved by the lifting guide 1032A. Themounting table 1032B, together with the wafer boats 1031A and 1031B, isintroduced into the heat treatment furnace 1028 to serve as a lid forclosing a bottom end opening 1028A of the heat treatment furnace 1028.

In the vicinity of the bottom end opening 1028A of the heat treatmentfurnace 1028, there is provided a shutter 1033 for closing the bottomend opening 1028A when the wafer boat after heat treatment is carriedout of the heat treatment furnace 1028. The shutter 1033 is designed tobe rotated by a shutter driving mechanism about a vertically extendingshaft to be open and closed.

On one side portion of the housing 1011 in the loading area Sb, there isprovided a boat mounting portion 1035 serving as a holder mountingportion on which the wafer boats 1031A and 1031B are supported fortransferring the semiconductor wafers. The boat mounting portion 1035has first and second mounting portions 1035A and 1035B which arearranged in longitudinal directions.

In the loading area Sb, there is provided a boat transfer mechanism 1036which is a holder transfer mechanism for transferring the wafer boats1031A and 1031B between the first mounting portion 1035A or secondmounting portion 1035 of the boat mounting portion 1035 and the mountingtable 1032B of the boat elevator mechanism 1030 and between the firstmounting portion 1035A and the second mounting portion 1035B.

The boat transfer mechanism 1036 comprises a first arm 1036A which isrotatable on the horizontal plane and which is movable in verticaldirections, and a supporting arm 1036B which is provided on the tipportion of the first arm 1036A so as to be rotatable on the horizontalplane and which has a substantially C-shaped opening 1036C capable ofvertically supporting the wafer boats 1031A and 1031B.

The supporting arm 1036B is arranged so that the locus of the center ofthe opening 1036C when being driven includes the rotation center of thefirst arm 1036A. By rotating the first arm 1036A and the supporting arm1036B in synchronism with each other, the wafer boats 1031A and 1031Bare transferred on the horizontal plane.

At a level above the lowest position of the boat transfer mechanism1036, there is provided a wafer transfer mechanism 1040 which has amotion space region overlapping with the motion space region of the boattransfer mechanism 1036 and which is a treating-object transfermechanism for transferring the semiconductor wafers between the carrier1020 on the carrier mounting portion 1021 and the wafer boat 1031B onthe boat mounting portion 1035.

As shown in FIG. 11, the wafer transfer mechanism 1040 comprises: alifting guide 1041 which is provided on the opposite side face to theboat mounting portion 1035 via a part of the motion space region of theboat transfer mechanism 1036; a swivel arm 1042 which is movable invertical directions by means of the lifting guide 1041 and which isrotatable about a vertically extending shaft 1421; an elongatedrectangular transfer head 1043 which is provided on the tip portion ofthe swivel arm 1042 so as to be rotatable on the horizontal plane; and asupporting arm 1044 which comprises one or a plurality of, e.g., one tofive, fork-shaped thin plates and which is provided on the transfer head1043 so as to be retractable in their longitudinal directions.

Means for driving the wafer transfer mechanism 1040 comprises astretching mechanism 1045 for rotating the swivel arm 1042, and a belttransmission mechanism for transmitting the rotational motion of theswivel arm 1042 to the transfer head 1043.

For example, the stretching mechanism 1045 comprises an air cylinder.One end of the stretching mechanism 1045 is rotatably connected to arotation center shaft 1451 which is different from the rotation centershaft 1421 of the swivel arm 1042, and the other end is rotatablyconnected to a connecting portion (1056 in FIG. 12) in the tip sideportion of the swivel arm 1042. The stretching direction of thestretching mechanism 1045 obliquely traverses the longitudinal directionof the swivel arm 1042.

The stretching mechanism 1045 is adjusted so that the whole lengththereof expands and contracts in the range of, e.g., from 195 to 250 mm.Thus, the motion space region of the wafer transfer mechanism 1040 isset to be in a predetermined range, and the direction or angular stateof the swivel arm 1042 can be surely controlled.

For example, as shown in FIG. 12, the belt transmission mechanismserving as the means for driving the transfer head 1043 comprises belttransmission mechanisms 1051A and 1051B wherein belts 1054A and 1054Bare tensionally extended between and wound onto pulleys and which arecombined with each other in two stages. Specifically, the center shaft1511 of a fixed pulley 1052A of one belt transmission mechanism 1051A isarranged while being fixed to the rotation center shaft 1421 of theswivel arm 1042, and the rotation center shaft 1512 of a driven pulley1053B of the other belt transmission mechanism 1051B is fixed to therotation center shaft 1431 of the transfer head 1043. In addition, thedriven pulley 1053A of the one belt transmission mechanism 1051A and thedriving pulley 1052B of the other belt transmission mechanism 1051B arefixed to each other so that the their rotation center shafts arecoincident with each other. In the figure, reference number 1055 denotesa tension pulley for increasing the winding angle of the driven pulley1053B and driving pulley 1052B of the other belt transmission mechanism1051B.

The driven pulley 1053A of the one belt transmission system 1051A has asmaller diameter than that of the fixed pulley 1052A, and the pulleyratio of the fixed pulley 1052A to the driven pulley 1053A is set to be,e.g., 42:24.

The pulley ratio of the driving pulley 1052B to the driven pulley 1053Bin the other belt transmission system is set to be, e.g., 1:1.

According to this driving means, the swivel arm 1042 is rotated aboutthe rotation center shaft 1421 on its one end by the expansion andcontraction of the stretching mechanism 1045, so that the driven pulley1053A of the one belt transmission system 1051A is rotated in theopposite direction to the rotational direction of the swivel arm 1042.In accordance therewith, the driving pulley 1052B of the other belttransmission system 1051B is rotated, and the driven pulley 1053B of theother belt transmission system 1051B is rotated via the belt 1054B. As aresult, the transfer head 1043 is rotated by a rotational angleaccording to the rotational angle of the swivel arm.

The operation of the above described vertical heat treatment system 1010will be described below.

First, if the carrier 1020 is mounted on the carrying-in/out stage 1014from the outside by an automatic transfer robot (not shown) or anoperator, the carrier 1020 is carried in via the carrying-in/out opening1013, and the sensor mechanism 1015 opens the lid of the carrier 1020 todetect the positions and number of semiconductor wafers in the carrier1020. Thereafter, while the lid 1020A of the carrier 1020 is closed, thecarrier 1020 is transferred to the notch aligning mechanism by means ofthe carrier transfer mechanism 1025, and transferred to the carriermounting portion 1021 after notches (cut-out portions), which are formedin the peripheral edge portions of the semiconductor wafers, are alignedin one direction. In addition, in accordance with the progression of theheat treatment, the carrier 1020 is stored in the carrier storageportion 1016 once, and thereafter, transferred to the carrier mountingportion 1021.

If the lid 1020A of the carrier 1020 on the carrier mounting portion1021 and the door 1023 of the opening 1022 of the partition wall 1012are open, the semiconductor wafers are taken out of the carrier 1020 tobe sequentially transferred to the wafer boat 1031B, which stands by onthe first mounting portion 1035A of the boat mounting portion 1035, bymeans of the wafer transfer mechanism 1040, specifically by carrying outthe rotation of the swivel arm 1042, the rotation of the transfer head1043 and the expansion and contraction of the supporting arm 1044 in acontrolled state. Meanwhile, the boat transfer mechanism 1036 is moveddownwards to the lower position to take shelter, so that the wafertransfer mechanism 1040 does not interfere with the boat transfermechanism 1036.

If the transfer of the semiconductor wafers from the carrier 1020 on thecarrier mounting portion 1021 to the wafer boat 1031B on the firstmounting portion 1035A is completed, the wafer transfer mechanism 1040is transferred from its motion space region to a sheltered position onthe other side face of the housing 1011.

Specifically, if the stretching mechanism 1045 is contracted as shown inFIG. 13( b) after the wafer transfer mechanism 1040 is moved to aspecific reference position in its motion space region as shown in FIG.13( a), the swivel arm 1042 is rotated about its rotation center shaft1421, and simultaneously, the transfer head 1043 is rotated by the belttransmission mechanism, which is means for driving the transfer head1043, by a rotational angle corresponding to the rotational angle of theswivel arm 1042 to be transferred to a predetermined sheltered position.That is, as shown in FIG. 14, while the transfer head 1043 in the wafertransfer mechanism 1040 is rotated (revolved) clockwise around therotation center shaft 1421 of the swivel arm 1042, the transfer head1043 itself is rotated (rotated on its axis) in the reverse direction ofthe direction of rotation of the swivel arm 1042 (counterclockwise) tobe moved on the horizontal plane along the outer peripheral edge of themounting table 1032B in the boat elevator mechanism 1030.

The reference position of the wafer transfer mechanism 1040 in themotion space region is previously set in accordance with, e.g., thepulley ratio of one belt transmission system 1051A in the means fordriving the transfer head 1043. Thus, the above described shelteredmotion is surely carried out, and the wafer transfer mechanism 1040 istransferred to a predetermined sheltered position.

In this state, the wafer boat holding the semiconductor wafers on thefirst transfer portion 1035A of the boat transfer portion 1035 istransferred to the mounting table 1032B in the boat elevator mechanism1030 by means of the boat transfer mechanism 1036, and then, the waferboat, together with the mounting table 1032B, is introduced into theheat treatment furnace 1028 by means of the boat elevator mechanism1030. Then, the boat transfer mechanism 1036 is moved to a shelteredposition below its motion space region, and one wafer boat isheat-treated. Simultaneously, the transfer of the semiconductor wafersfor the wafer boat on the first transfer portion 1035A is carried out inparallel.

After the heat treatment is completed, the mounting table 1032B is moveddownwards to cause the wafer boat after the heat treatment to be carriedout of the heat treatment furnace 1028 into the loading area Sb, and thebottom end opening 1028A of the heat treatment furnace 1028 isimmediately closed by the shutter 1033.

If the wafer boat after the heat treatment is carried out, the waferboat 1031B before the heat treatment, which stands by on the firstmounting portion 1035A, is first transferred to the second mountingportion 1035B by means of the boat transfer mechanism 1036. Then, thewafer boat 1031A after the heat treatment is transferred from themounting table 1032B to the first mounting portion 1035A, and finally,the wafer boat 1031B on the second mounting portion 1035B is transferredto the mounting table 1032B.

Then, the semiconductor wafers are taken out of the wafer boat 1031A bymeans of the wafer transfer mechanism 1040 after the heat treatment, tobe loaded in the carrier 1020 on the carrier mounting portion 1021 to betransferred by means of the carrier transfer mechanism 1025 to becarried out via the carrying-in/out opening 1013.

According to the above described heat treatment system 1010, the wafertransfer mechanism 1040 is moved on the horizontal plane, not above theboat transfer mechanism 1036, to take shelter on the side face of thehousing 1011, so that the wafer boat during the transfer does notinterfere with the wafer transfer mechanism 1040. In addition, since thewafer transfer mechanism 1040 at the lower position takes shelter on thesame plane as that of the elevator mechanism, the influence of heat fromthe heat treatment furnace can be very small, so that the heat treatmentsystem can be stably operated for a long term.

When the wafer transfer mechanism 1040 is moved from the motion spaceregion to the sheltered position, the transfer head 1043 of the wafertransfer mechanism 1040 is moved on the horizontal plane along the outerperipheral edge of the mounting table 1032B of the boat elevatormechanism 1030 at the lowest position, i.e., through an arc-shapedpassage which is curved in the opposite direction to the locus L of therotation center shaft 1431 of the transfer head 1043. Therefore, thespace required for the sheltered motion of the wafer transfer mechanism1040 can be reduced. In addition, in the loading area Sb, the boatmounting portion 1035 and the boat elevator mechanism 1030 can bearranged at a high spatial utilization factor. For example, the distancebetween the carrier mounting portion 1021 and the boat elevatormechanism 1030 can be smaller than the conventional distance by about 20to 30%. Therefore, it is possible to miniaturize the whole system whilemaintaining a high throughput.

An example of dimensions in the above described vertical heat treatmentsystem 1010 will be described below. At the reference position(sheltered motion starting position) in the motion space region for thewafer transfer mechanism 1040, the rotational angle α of the swivel arm1042 with respect to the side wall face of the housing 1011 is 64.5°,the rotational angle β of the transfer head 1043 with respect to thecenter shaft of the swivel arm 1042 in longitudinal directions is 39.5°,the overall length of the stretching mechanism 1045 is 247.6 mm (seeFIG. 13( a)), and the overall length of the stretching mechanism 1045 is198.5 mm when the wafer transfer mechanism 1040 is positioned at itssheltered position.

While the preferred embodiment of the present invention has beendescribed above, the operation of the present invention should not belimited to the above described operation. For example, the object to betreated may be transferred from the carrier on the carrier mountingportion directly to the wafer boat on the mounting table in the boatelevator mechanism. This is particularly useful when a small number ofvarious objects to be treated are treated.

While the heat treatment in one wafer boat is carried out, when thetransfer of the semiconductor wafers with respect to the other waferboat on the first transfer portion is completed, the transfer of thewafer boat from the first mounting portion to the second mountingportion may be previously carried out by means of the boat transfermechanism.

In the transfer head driving means, the driven pulley of onetransmission mechanism rotated by the rotation of the swivel arm may beintegrally formed with the driven pulley of the other belt transmissionmechanism to which the transfer head is connected.

The objects treated in the vertical heat treatment system according tothe present invention should not be limited to semiconductor wafers. Forexample, the vertical heat treatment system according to the presentinvention is suitably used for heat-treating glass wafers or ceramicwafers.

According to the vertical heat treatment system of the second invention,the treating-object transfer mechanism is caused to take shelter on oneside face of the housing when the holder is transferred. Therefore, theholder does not interfere with the treating-object transfer mechanismduring the transfer of the holder. In addition, since the liftingmechanism takes shelter on the same plane when the lifting mechanism ispositioned at its lower position, the influence of heat from the heattreatment furnace or the like can be very small, and the system can bestably operated for a long term.

In addition, since the transfer head of the treating-object transfermechanism is moved along the outer peripheral edge of the holdersupporting face of the lifting mechanism, the holder mounting portionsand so forth can be arranged in the loading area while the spacerequired for the sheltered motion is very small. Therefore, it ispossible to miniaturize the whole system while maintaining the highthroughput.

According to the method for controlling the vertical heat treatmentsystem according to the second invention, it is possible to surelyprevent the holder from interfering with the treating-object transfermechanism during the transfer of the holder, and the influence of heatfrom the heat treatment furnace and so forth can be very small, so thatit is possible to stably operate the vertical heat treatment system.

Moreover, since the transfer head of the treating-object transfermechanism can be caused to take shelter in a relatively small space, theholder mounting portion and so forth can be arranged at a high spatialutilization factor, so that it is possible to miniaturize the wholesystem while maintaining the high throughput.

Referring to the accompanying drawings, the third invention will bedescribed below in detail.

First Preferred Embodiment

(Schematic Construction of Whole Heat Treatment System)

Referring to the accompanying drawings, the preferred embodiment of thethird invention will be described below in detail.

FIG. 15 is a schematic perspective view of a vertical heat treatmentsystem according to the third invention.

As shown in FIG. 15, a housing 2010 defining the contour of a verticalheat treatment system is separated by a partition wall 2012 into acarrier transfer area Sa and a loading area Sb.

In the carrier transfer area Sa, the carrying-in/out, storage and soforth of a carrier, in which semiconductor wafers W (which will behereinafter referred to as wafers W) serving as objects to be treated(which will be also hereinafter referred as substrates to be treated)have been housed, are carried out. In the loading area Sb, the transferof the wafers W from the interior of the carrier 2014 to a holder (whichwill be also hereinafter referred to as a boat) 2016, and the carryingof the holder 2016 in and out of a heat treatment furnace 2018, and soforth are carried out.

Clean air is supplied to the carrier transfer area Sa via a filter (notshown), so that the carrier transfer area Sa is maintained in anatmosphere of atmospheric air. Clean air or an inert gas, e.g., nitrogengas, is supplied to the loading area Sb, so that the loading area Sb ismaintained in an atmosphere of atmospheric air or an atmosphere of theinert gas.

The carrier 2014 is a so-called closed type carrier, which housestherein a plurality of wafers W and which is closed by an FIMS(Front-opening Interface Mechanical Standard) door 2015. Specifically,the carrier 2014 is a portable plastic vessel capable of housing thereina plurality of, e.g., about 13 to 25, semiconductor wafers having apredetermined diameter, e.g., a diameter of 300 mm, in a horizontalstate on multiple stages at regular intervals in vertical directions,and the FIMS door 2015 is detachably provided for airtightly closing awafer outlet which is formed in the front face of the vessel.

The front face portion of the housing 2010 is provided with a carriercarrying-in/out opening 2020 for carrying the carrier 2014 in and out bymeans of an operator or a transfer robot. The carrier carrying-in/outopening 2020 is provided with a load port 2022 for carrying the carrier2014 in or out of the carrier transfer area Sa. By means of a transfermechanism 2024 provided on the load port 2022, the carrier 2014 is movedon the load port 2022 to be transferred to the interior of the carriertransfer area Sa.

In the carrier transfer area Sa, shelf-like storage portions 2026 forstoring a plurality of carriers 2014 are provided above the load port2022 and above the side of the partition wall 2012.

On the side of the partition wall 2012 in the carrier transfer area Sa,a carrier mounting portion (which will be also hereinafter referred toas an FIMS port) 2027 is provided for supporting thereon the carrier2014 to transfer the wafers. In the carrier transfer area Sa, a carriertransfer mechanism 2028 is provided for transferring the carrier 2014between the load port 2022, the storage portion 2026 and the carriermounting portion 2027.

The carrier transfer mechanism 2028 comprises: a lifting arm 2028 bwhich is vertically moved by a lifting mechanism 2028 a provided on oneside portion of the carrier transfer area Sa; an arm 2028 c which isprovided on the lifting arm 2028 b; and a transfer arm 2028 d which isprovided on the arm 2028 c for supporting thereon the bottom of thecarrier 2014 to transfer the carrier 2014.

The partition wall 2012 is provided with a door 2030 which is formed soas to have a shape corresponding to the wafer outlet of the carrier 2014and which is capable of being open and closed. By opening the door 2030while the carrier 2014 contacts the door 2030, the wafers W in thecarrier 2014 can be taken in and out of the loading area Sb.

On the other hand, above the inside of the loading area Sb, a lid 2032is provided so as to be capable of being vertically moved by a liftingmechanism (which will be also hereinafter referred to as a boatelevator) 2034. The lid 2032 can support thereon the holder 2016 of,e.g., quartz, which holds a plurality of, e.g., about 100 to 150, wafersW on multiple stages at regular intervals in vertical directions. Byvertically moving the lid 2032 by means of the lifting mechanism 2024,the holder 2016 holding the wafers W can be carried in and out of theheat treatment chamber of the heat treatment furnace 2018. In thevicinity of the throat of the heat treatment furnace 2018, there isprovided a shutter 2026 which is capable of being open and closed inhorizontal directions for closing the throat when the lid 2032 is moveddownwards and when the holder 2016 is carried out after the heattreatment.

In one side portion of the loading area Sb, a first holder mountingportion (which will be also hereinafter referred to as a holdingsupporting mechanism or a boat stage) 2028 is provided for supportingthereon the holder 2016 in order to transfer the wafers W. Behind thefirst holder mounting portion 2038, a second holder mounting portion(which will be also hereinafter referred to as a standby stage) 2040 isprovided for supporting thereon the holder 2016 which holds the wafers Wserving as the objects to be treated.

Between the carrier transfer portion 2027 and the heat treatment furnace2018 in the lower portion in the loading area Sb, a holder transfermechanism 2042 is provided for transferring the holder 2016 between thefirst holder mounting portion 2023, the second holder mounting portion2040 and the lid 2017.

The holder transfer mechanism 2042 comprises a first arm 2042 a capableof being rotated in horizontal directions and moved in verticaldirections, and a supporting arm 2042 b which is supported on the tipportion of the first arm 2014 a so as to be rotatable in horizontaldirections and which is capable of supporting the holder 2016 invertical directions, the supporting arm 2042 b having a substantiallyC-shaped opening.

Above the holder transfer mechanism 2042, a transfer mechanism 2044 isprovided for transferring the wafers W between the carrier 2014 on thecarrier transfer portion 2027 and the holder 2016 on the first holdermounting portion 2038. The transfer mechanism 2044 comprises a liftingmechanism 2044 a, a first arm 2044 b which is connected to the liftingmechanism 2044 a and which is rotatable in horizontal directions, asecond arm 2044 c which is connected to the first arm 2044 b and whichis rotatable in horizontal directions, and a supporting arm 2044 d whichis provided on the second arm 2044 c and which is retractable. Thesupporting arm 2044 d comprises a plurality of, e.g., two to five,fork-shaped thin plates, and is movable while supporting thereon thewafers W.

The procedure for heat-treating wafers W in the vertical heat treatmentsystem with this construction will be described below.

After the carrier 2014 is supported on the load port 2022, the transfermechanism 2024 transfers the carrier 2014 to the carrier transfer areaSa via the carrier carrying-in/out opening 2020. Then, the carrier 2014on the load port 2022 in the carrier transfer area Sa is transferred tothe storage portion 2026 by means of the carrier transfer mechanism2028. Moreover, the carrier 2014 in the storage portion 2026 istransferred to the carrier mounting portion 2027 by means of the carriertransfer mechanism 2028.

If the FIMS door 2015 of the carrier 2014 on the carrier mountingportion 2027 and the door 2030 of the partition wall 2012 are open, thetransfer mechanism 2044 takes the semiconductor wafers W out of thecarrier 2014 to sequentially transfer the wafers W to an empty holder2016 which stands by on the first holder mounting portion 2038.

By the holder transfer mechanism 2024, the holder 2016 holding thewafers W is transferred to the top face of the lid 2032 from the firstholder mounting portion 2038, via the second holder mounting portion2040 if necessary. The holder 2016 on the lid 2032 holding the wafers Ware housed in the heat treatment chamber of the heat treatment furnace2018 by means of the lifting mechanism 2034, and a heat treatment iscarried out therein. Furthermore, when the lid 2032 moves in verticaldirections, the shutter 2036 is caused to take shelter.

After the heat treatment is completed, the lid 2032 is moved downwardsby means of the lifting mechanism 2034, and the holder 2016 is carriedout of the heat treatment chamber of the heat treatment furnace 2018 tobe transferred to the loading area Sb. The holder 2016 which is carriedout of the heat treatment chamber of the heat treatment furnace 2018 andwhich holds the heat-treated wafers W is transferred from the top faceof the lid 2032 to the top face of the first holder mounting portion2038. The wafers W are moved from the holder 2016, which is arranged onthe first holder mounting portion 2038, to the carrier 2014, which isarranged on the carrier mounting portion 2017, by means of the transfermechanism 2044.

The carrier 2014 housing therein the heat-treated wafers W is mounted onthe load port 2022 by means of the carrier transfer mechanism 2028, andis carried out of the carrier carrying-in/out opening 2020 by means ofthe transfer mechanism 2024.

(Details of First Holder Mounting Portion)

The first holder mounting portion (boat stage) 2038 will be describedbelow in detail. FIG. 16 is a partially sectional view of the firstholder mounting portion 2038 viewed from the top. FIGS. 17 and 18 arepartially sectional views of the first holder mounting portion 2038taken along lines A-B and C-D of FIG. 15, respectively. FIGS. 19 and 20are side views of the first holder mounting portion 2038 viewed in thedirections of arrows E and F of FIG. 15, respectively.

In FIGS. 17 and 18, a holder bottom plate 2160 of the holder 2016 isshown by a two-dot chain line. The holder bottom plate 2160 has a flatring shape having a circular outer periphery 2162, a part of which iscut by a straight line, and a substantially circular opening portion(inner periphery) 2164 which is concentric with the outer periphery2162. The opening portion 2164 has a pair of cut-outs 166 a and 166 b inthe vicinity of both ends in radial directions. Each of the cut-outs 166a and 166 b has a substantially isosceles triangular shape which issymmetrical with respect to the center of the opening portion 2164, andthe vertex thereof is rounded.

The first holder mounting portion 2038 comprises a holder mounting table2050 for mainly supporting thereon the holder 2016, a base 2056 fixed tothe heat treatment system, and a ball retainer 2062 for retaining aspherical ball 2060 which is arranged between the holder mounting table2050 and the base 2056. On the holder mounting table 2050, a pair ofsubstantially cylindrical protruding portions 2068 a and 2068 b arearranged for positioning the holder 2016. The holder mounting table 2050comprises a disk-shaped holder mounting table body 2050 a, and a narrowflat ring-shaped top rail portion 2050 b which is substantiallyconcentric with the holder mounting table body 2050 a and which has anouter periphery having a slightly smaller diameter than that of theholder mounting table body 2050 a.

The holder mounting table body 2050 a is formed with a circuit openingportion 2052 which is substantially concentric with the holder mountingtable body 2050 a, and a pair of circular opening portions 2054 a and2054 b which correspond to the protruding portions 2068 a and 2068 b andwhich are symmetrical with each other with respect to the center of theholder mounting table body 2050 a.

The base 2056 comprises a flat ring-shaped base top plate 2056 a whichsubstantially corresponds to the holder mounting table body 2050 a, aflat ring-shaped bottom rail portion 2056 b which is arranged on the topface of the base top plate 2056 a and which substantially corresponds tothe top rail portion 2050 b, a substantially cylindrical connectingportion 2056 c which is connected to the lower portion of the base topplate 2056 a, and a flat ring-shaped base bottom plate 2056 d which isconnected to the connecting portion 2056 c. The base top plate 2056 a isformed with a pair of substantially circular opening portions 2058 a and2058 b, the positions and shapes of which correspond to those of theopening portions 2054 a and 2054 b of the holder mounting table 2050,respectively.

The base top plate 2056 a is formed with a pair of substantiallyrectangular opening portions 2057 a and 2057 b on its outer periphery onboth ends in radial directions. Furthermore, the ball retainer 2062 andthe bottom rail portion 2056 b are formed continuously even in theopening portions 2057 a and 2057 b.

The ball retainer 2062 has a flat ring shape which substantiallycorresponds to the top rail portion 2050 b and the bottom rail portion2056 b. The thickness of the ball retainer 2062 is smaller than thediameter of the ball 2060. The ball retainer 20623 is formed with acircular opening portion which has a slightly greater diameter than thediameter of the ball 2060, and the ball 2060 is retained in this openingportion.

The ball 2060 retained in the ball retainer 2062 rotates between the toprail portion 2050 b and the bottom rail portion 2056 b. Therefore,friction during sliding motion between the top rail portion 2050 b andthe bottom rail portion 2056 b is reduced by the ball 2060.

That is, according to the third invention, the combination of the ball2060 with the ball retainer 2062 for retaining the same functions as asliding mechanism for facilitating motion along the principal plane ofthe holder mounting table 2050 (the top or bottom face of the holdermounting table body 2050 a) between the holder mounting table 2050 andthe base 2056. Furthermore, this motion may include rotational motionabout an axis perpendicular to the principal part of the holder mountingtable 2050.

The protruding portions 2068 a and 2068 b are connected to shafts 2066 aand 2066 b, respectively, which are connected to air cylinders 2068 aand 2068 b, respectively, which are provided on the base bottom plate2056 d. The shafts 2066 a and 2066 b have an L shape, and pass throughthe opening portions 2058 a and 2058 b of the base 2056 and the openingportions 2054 a and 2054 b of the holder mounting table 2050,respectively.

Air or nitrogen gas is supplied to each of the air cylinders 2064 a and2064 b (gas piping is not shown), so that the shafts 2066 a and 2066 bcan be pushed out or pulled back toward the center of the base 2056 bytheir gas pressures, respectively. If the shafts 2066 a and 2066 b arepushed out or pulled back, the protruding portions 2068 a and 2068 bmove so as to approach or leave the center of the base 2056,respectively.

In FIGS. 16 and 17, the solid line shows the state that the gaspressures in the air cylinders 2064 a and 2064 b are reduced to pullboth of the shafts 2066 a and 2066 b back.

By the operation of the air cylinders 2064 a and 2064 b, the distancebetween the centers of the protruding portions 2068 a and 2068 b variesbetween the maximum value L2 and the minimum value L1. Furthermore, atthis time, the relationship between the stroke ΔL of the air cylinders2064 a, 2064 b and the maximum value L2 and minimum value L1 of thedistance between the protruding portions 2068 a and 2068 b is L2=L1−2ΔL.

If the distance between the protruding portions 2068 a and 2068 b isincreased, the protruding portions 2068 a and 2068 b enter (engage) thecut-outs 166 a and 166 b, which are provided in the holder bottom plate2160, respectively, to stop in the vicinity of the vertexes of thecut-outs 166 a and 166 b, respectively.

At this time, if the holder 2016 is positioned at a predeterminedposition and in a predetermined direction on the base 2056 (at thecenter of the base 2056 and in a direction in which the cut-outs 166 aand 166 b correspond to the protruding portions 2068 a and 2068 b), therelationship between the positions and directions of the holder 2016 andthe base 2056 is maintained.

On the other hand, if the arrangement of the holder 2016 is shifted fromthis predetermined arrangement, the holder 2016 moves in accordance withthe movement of the protruding portions 2068 a and 2068 b, so that theposition and direction of the holder 2016 with respect to the base 2056vary. That is, the holder 2016 moves on the base 2056, so that itsposition is adjusted to a predetermined position. That is, theprotruding portions 2068 a and 2068 b function as a holder positionadjusting mechanism for adjusting the position of the holder 2016 on thebasis of the correspondence to the cut-outs formed in the holder bottomplate 2160.

Since the ball retained in the ball retainer 2062 functions as a slidingmechanism when the position of the holder is adjusted, the holdermounting table 2050 can move with the holder 2016. As a result, theforce of the air cylinders 2064 a and 2064 b is not so great, theposition of the holder 2016 can be easily adjusted.

A pair of air cylinder holders 2070 a and 2070 b are mounted on thebottom face of the holder mounting table 2050 by means of screws 2072 aand 2072 b so as to correspond to the opening portions 2057 a and 2057 bof the base 2056, respectively. The air cylinder holders 2070 a and 2070b hold the air cylinders 2074 a and 2074 b, respectively.

As a result, the air cylinders 2074 a and 2074 b are arranged in theopening portions 2057 a and 2057 b of the base 2056 so as to correspondto the bottom rail portion 2056 b, respectively. Shafts 2076 a and 2076b protrude from the air cylinders 2074 a and 2074 b, respectively, andsubstantially cylindrical moving pieces 2077 a and 2077 b are formed onthe tips of the shafts 2076 a and 2076 b, respectively.

The moving pieces 2077 a and 2077 b are formed of an elastic material ofrubber or the like. The shafts 2076 a and 2076 b extend in a directionperpendicular to the principal plane of the base 2056, and the movingpieces 2077 a and 2077 b face the bottom rail portion 2056 b at smalldistances da and db, respectively. Air or nitrogen gas is supplied tothe air cylinders 2074 a and 2074 b (gas piping is not shown), so thatthe moving pieces 2077 a and 2077 b connected to the shafts 2076 a and2076 b can be pushed against or pulled back from the bottom rail portion2056 b by the gas pressure (the distances da and db vary).

By pushing the moving pieces 2077 a and 2077 b against the bottom railportion 2056 b, the holder mounting table 2050 can be stopped on thebase 2056. This is based on the fact that the air cylinders 2074 a and2074 b, to which the moving pieces 2077 a and 2077 b are connected, arefixed to the holder mounting table 2050, and on the other hand, thebottom rail portion 2056 b constitutes a part of the base 2056. Asdescribed above, the air cylinders 2074 a and 2074 b having the movingpieces 2077 a and 2077 b function as a mounting table fixing mechanismfor fixing the holder mounting table 2050 to the base 2056.

Three plate springs 2078 a, 2078 b and 2078 c are mounted on the sideface of the base 2056 by screws 2080 a, 2080 b and 2080 c atsubstantially even intervals, respectively. The plate spring 2078comprises a substantially rectangular fixing portion 2782, two pairs ofelastic portions 2874 a and 2784 b formed on the fixing portion 2782,and elastic portions 2786 a and 2786 b. The elastic portions 2784 a and2784 b contact the side face of the top rail portion 2050 b in thevicinity of their end portions, and the elastic portions 2786 a and 2786b contact the side face of the ball retainer 2062 in the vicinity oftheir end portions, so that a biasing force is applied toward the centerof the base 2056.

That is, the elastic portions 2784 a and 2784 b function as biasingmeans for applying a biasing force to the holder mounting table 2050toward the center of the base 2056, and the elastic portions 2786 a and2786 b function as biasing means for applying a biasing force to thesliding mechanism (the ball 2060 and the ball retainer 2062) toward thecenter of the base 2056.

Finally, the three plate springs 2078 a, 2078 b and 2078 c function asbiasing means for applying a biasing force to both of the slidingmechanism and the holder mounting table 2050 toward the center of thebase 2056 from three directions.

That is, the three plate plates 2078 a, 2078 b and 2078 c function as amounting table position returning mechanism for returning the positionof the holder mounting table 2050 to a predetermined position (thecenter of the base 2056) and a sliding mechanism returning mechanism forreturning the sliding mechanism to a predetermined position (the centerof the base 2056).

Between the holder mounting table 2050 and the base 2056, a pair ofhelical springs 2082 a and 2082 b are provided. The both ends of thehelical springs 2082 a and 2082 b are connected to a substantiallyL-shaped first spring fixture 2084, which is mounted on the outerperiphery of the holder mounting table body 2050 a, and a pair of secondspring fixtures 2086 a and 2086 b which are connected to the base topplate 2056 a so as to surround the tip of the first spring fixture 2084.

The helical springs 2082 a and 2082 b extend along the outer peripheryof the base 2056 to connect the holder mounting table 2050 to the base2056. Therefore, when the holder mounting table 2050 is rotated withrespect to the base 2056, a biasing force is applied so as to inverselyrotate the holder mounting table 2050 with respect to the base 2056.

That is, the helical springs 2082 a and 2082 b function as a mountingtable angle returning mechanism for intending to return the relativeangle of the holder mounting table 2050 with respect to the base 2056 tothe angle before rotation. As a result, in corporation with the mountingtable position returning mechanism, for example, the positionalrelationship between the opening portions 2054 a, 2054 b of the holdermounting table 2050 and the shafts 2066 a, 2066 b, and the positionalrelationship between the air cylinders 2074 a, 2074 b and the openingportions 2057 a, 2057 b of the base 2056 are always maintained inappropriate states.

(Conceptual Explanation of First Holder Mounting Portion)

FIG. 21 is a conceptual view simply showing the construction of thefirst holder mounting portion (boat stage) 2038 shown in FIGS. 16through 20. FIGS. 21A and 21B are top (corresponding to FIG. 16) andpartially sectional (corresponding to FIGS. 17 through 19) views of thefirst holder mounting portion 2038, respectively. The left half of FIG.21B mainly corresponds to FIG. 17, and the right half of FIG. 21Bsubstantially corresponds to FIG. 18.

Between the holder mounting table 2050 and the base 2056, the ball 2060serving as the sliding mechanism allows movement along the principalplane of the holder mounting table 2050 and rotation with respect to anaxis perpendicular to the principal plane.

The pair of protruding portions 2068 a and 2068 b serving as the holderposition adjusting mechanism are arranged so as to be symmetrical withrespect to the center of the base 2056 on the opening, portion on theholder mounting table. The distance between the protruding portions 2068a and 2068 b can be changed by the air cylinders 2064 a and 2064 b. Theprotruding portions 2086 a and 2086 b enter the pair of cut-outs 166 aand 166 b, which are formed in the opening portion 2164 of the holderbottom plate 2160, to adjust the position of the holder 2016.

The moving piece 2077 of the air cylinder 2074 functions as a mountingtable fixing mechanism for fixing the holder mounting table 2050 to thebase 2056. In FIG. 18, the air cylinder 2074 is connected to the holdermounting table 2050, whereas in FIG. 21, the air cylinder 2074 is fixedto the base 2056. The difference between FIGS. 18 and 21 is based on thefact that the former regards space saving as important and the latterregards facilitation of understanding as important. Even if the aircylinder 2074 is fixed to any one of the holder mounting table 2050 andthe base 2056, the moving piece 2077 blocks the relative movementbetween the holder mounting table 2050 and the base 2056.

Each of the three springs 2078 a, 2078 b and 2078 c functions as abiasing means for applying a biasing force to the holder mounting table2050 in three directions toward the center of the base 2056. These threeplate springs 2078 a, 2078 b and 20768 c function as a mounting tableposition returning mechanism for returning the position of the holdermounting table, as a whole.

The pair of springs 2082 a and 2082 b function as a mounting table anglereturning mechanism for returning the angular relationship between theholder mounting table and the base 2056.

(Procedure for Transferring Objects to Holder)

The procedure for transferring wafers W to the holder 2016 on the firstholder mounting portion (boat stage) will be described below in detail.FIGS. 22 through 27 are schematic diagrams showing the state of thefirst holder mounting portion in this procedure, and FIG. 28 is a flowchart showing the transfer procedure.

-   (1) The holder mounting table 2050 (FIG. 22), on which the holder    2016 has not been mounted, is mounted on the holder 2016 (step S10    and FIG. 23).

The mounting of the holder 2016 on the holder mounting table 2050 iscarried out by the above described holder transfer mechanism 2042 (seeFIG. 15). At this time, there is some possibility that the center C2 ofthe mounted holder 2016 may be shifted from the center (referenceposition of holder to be transferred) C1 of the base 2056, so that thecenter C1 of the base 2056 may not be coincident with the center C2 ofthe holder 2016.

Furthermore, before the transfer of the holder 2016, it is assumed thatthe holder position adjusting mechanism (the protruding portion 2068 andthe air cylinder 2064) and the mounting table fixing mechanism (themoving piece 2077 and the air cylinder 2074) remain being released.

-   (2) The position of the holder is adjusted by the holder position    adjusting mechanism (the protruding portion 2068 and the air    cylinder 2064) (step S11 and FIG. 24).

The pair of protruding portions 2068 are moved so as to increase thedistance therebetween. Although the pair of protruding portions 2068 maybe moved at different times, the pair of protruding portions 2068 arepreferably simultaneously moved in view of the operation time.

The pair of protruding portions 2068 enter the tips of the pair ofcut-outs 166 a and 166 b, which are formed in the opening portion 2164of the holder bottom plate 2160, respectively, so that the position ofthe holder 2016 is adjusted (engagement of the cut-outs 166 with theprotruding portions 2068). For example, the tips of the cut-outs 166 aand 166 b are set to be symmetrical with respect to the center of theholder bottom plate 2160, and the pair of protruding portions 2068 aremoved to positions, which are symmetrical with respect to the center ofthe base 2056, respectively, so that the center C1 of the holder 2016can be coincident with the center C2 of the base 2056.

Since the holder mounting table 2050 can slide the base 2056 to movewith the holder 2016, it is possible to quickly move the holder 2016without any strong forces.

-   (3) The holder mounting table 2050 is fixed to the base 2056 by the    mounting table fixing mechanism (the moving piece 2077 and the air    cylinder 2074) (step S12).

This fixing is carried out by pushing the moving piece 2077 against theholder mounting table 2050 or the base 2056 by means of the air cylinderwhich is fixed to the holder mounting table 2050 or the base 2056.

This fixing step is carried out prior to step S13 in order to surelyprevent the movement of the holder mounting table 2050 during thetransfer of the wafers W at the next step S13.

If it is possible to prevent the movement of the holder 2016 by means ofthe protruding portions 2068 and the cut-outs 166, this fixing may becarried out immediately before the release of the adjustment of theposition of the holder at a subsequent step S14. The reason why thefixing of the holder mounting table 2050 is carried out prior to stepS14 is that it is required to prevent the movement of the holdermounting table 2050 during the release of the adjustment of the positionof the holder.

-   (4) The wafers W are transferred to the holder 2016 which is mounted    on the holder mounting table 2050 (step S13 and FIG. 25).

The wafers W serving as the objects to be treated are transferred andheld so that their edge portions are inserted into the grooves which areformed in the support of the holder 2016. This transfer is carried outby means of the above described transfer mechanism 2044 (see FIG. 15).

Since the position of the holder 2016 has been adjusted at step S11prior to this transfer, the wafers W serving as the objects to betreated can be precisely transferred to the holder 2016 (the control ofthe positional relationship between the wafers W and the holder 2016).

By precisely controlling the positions of the wafers W with respect tothe holder 2016, it is possible to easily ensure the uniformity of theheat treatment on the wafers W. On the other hand, if the precision ofthe position of the installed holder 2016 is bad, it is considered thatit is not only difficult to ensure the uniformity of the heat treatmenton the wafers W, but it is also possible to insert the wafers W into thegrooves of the support of the holder 2016.

-   (5) The holder position adjusting mechanism is released (step S14).

That is, the pair of protruding portions 2068 are moved toward thecenter of the base 2056 by the action of the air cylinder 2064, and theengagement with the holder bottom plate 2160 of the cut-outs 166 isreleased. At this time, the movement of the holder mounting table 2050is blocked by the action of the mounting table fixing mechanism (themoving piece 2077 and the air cylinder 2074).

-   (6) The holder 2016 is removed from the holder mounting table 2050    (step S15 and FIG. 26).

Also at this time similar to step S14, the movement of the holdermounting table 2050 is blocked by the action of the mounting tablefixing mechanism (the moving piece 2077 and the air cylinder 2074).

-   (7) The mounting table fixing mechanism (the moving piece 2077 and    the air cylinder 2074) is released to allow the holder mounting    table 2050 to relatively move with respect to the base 2056 (step    S16). That is, the moving piece 2077 does not contact the holder    mounting table 2050 or the base 2056 by the action of the air    cylinder 2074, so that the holder mounting table 2050 can be easily    moved by the action of the sliding mechanism (the ball 2060).

Thereafter, the center of the holder mounting table 2050 is coincidentwith the center C1 of the base 2056 by the action of the mounting tableposition returning mechanism (the springs 2078 a, 2078 b and 2078 c) andthe mounting table angle returning mechanism (the springs 2082 a and2082 b), so that the state of the holder mounting table 2050 returns tothe stage before the holder is mounted thereon (FIG. 15) (step S17 andFIG. 27).

Since the position of the holder mounting table 2050 before the mountingof the holder always returns to the same place, the amount of themovement of the holder mounting table 2050 with the adjustment of theposition of the holder 2016 can be ensured at step S11.

On the other hand, if the position of the holder mounting table 2050does not return, when the position of the holder 2016 mounted on theholder mounting table 2050 is shifted in the same direction as the lastmounting of the holder, there is some possibility that the holdermounting table 2050 can not sufficiently be moved.

As described above, the holder mounting portion (boat stage) accordingto the present invention has the holder position adjusting mechanism foradjusting the position of the holder to a predetermined position, sothat it is possible to precisely transfer and hold the objects to and inthe holder.

Other Preferred Embodiments

The above described preferred embodiments can be extended and changed,and the extended and changed preferred embodiments should be included inthe technical scope of the present invention.

-   (1) While the first holder mounting portion (boat stage) has been a    part of the heat treatment system in the above described preferred    embodiments, the first holder mounting portion may be separated from    the heat treatment system. For example, the objects to be treated    may be transferred to the holder in the holder mounting portion    outside of the heat treatment system, and thereafter, the holder to    which the objects to be treated have been completely transferred may    be transferred to the heat treatment system to carry out a heat    treatment therein.-   (2) The sliding mechanism should not limited to the combination of    the ball and the retainer for retaining the ball. For example, any    means for reducing friction between the holder mounting table and    the base, such as lubricant, may be used. In addition, the sliding    mechanism may be fixed to any one of the holder mounting table and    the base.-   (3) The holder position adjusting mechanism should not be limited to    the combination of the protruding portion and the air cylinder    connected to the protruding portion. The means for moving the    protruding portion should not be limited to the air cylinder. For    example, an electric means, such as an electric motor, may be used.

The place of the cut-outs corresponding to the protruding portionsshould not be limited to the opening portion formed in the holder bottomplate. For example, the cut-outs may be formed in the outer peripheralportion of the holder bottom plate. In this case, the distance betweenthe protruding portions decreases, so that the cut-outs engage theprotruding portions.

The shapes of the protruding portions and the cut-outs of the holdermounting table should not be limited to the cylindrical shape and thesubstantially triangular shape, respectively, if the protruding portionscan engage the cut-outs. For example, if recessed portions are providedin place of the protruding portions and if the holder is provided withprotruding portion in place of the cut-outs, the position of the holdercan be adjusted by the engagement of the recessed portions with theprotruding portions.

In addition, the number of the protruding portions should not be limitedto two. The numbers of the cut-outs and the corresponding protrudingportions may be three or more, respectively. For example, if threeprotruding portions are arranged on a circumstance and if theseprotruding portions move so as to approach or leave the center of thecircumstance, the protruding portions can engage the cut-outs.

Moreover, while both of the pair of protruding portions have been movedin the above described preferred embodiments, one of the protrudingportions may be fixed and only the other protruding portion may be movedto adjust the position of the holder.

-   (4) The components of the mounting table position returning    mechanism or mounting table angle returning mechanism should not be    limited to the plate springs or the helical springs. For example,    electric means or air may be used as the biasing means.

The number of the biasing means constituting the mounting table positionreturning mechanism should not be limited to three. For example, thebiasing force toward the same center may be applied to the holdermounting table by four or more biasing means.

Similarly, the mounting table angle returning mechanism should not belimited to the two biasing means. For example, the mounting table anglereturning mechanism may comprises three or more biasing means.

In short, the mounting table position returning mechanism or themounting table angle returning mechanism may be any means for applyingforce to return the position or angle of the holder mounting table to apredetermined position or angle if the position or angle of the holdermounting table is shifted from the predetermined position or angle. Forexample, the mounting table position returning mechanism or the mountingtable angle returning mechanism may be based on a magnetic force.

-   (5) The mounting table fixing mechanism should not be limited to the    combination of the air cylinder and the moving piece in the above    described preferred embodiments. The means for moving the moving    piece should not be limited to the air cylinder. For example, the    means for moving the moving piece may be electric means, such as an    electric motor.

As described above, the air cylinder may be fixed to any one of theholder mounting table and the base, or may be connected to a quitedifferent another component of the heat treatment system.

The shape and material of the moving piece may be suitably changed.

The objects to be treated, which have been transferred to the holder onthe holder mounting portion according to the third invention, are to beheat-treated by the heat treatment system while being held in theholder. At this time, since the objects to be treated are precisely heldin the holder, the objects to be treated are precisely transferred tothe holder, so that the objects to be treated can be more uniformlyheat-treated.

Referring to the accompanying drawings, the fourth invention will bedescribed below in detail.

Referring to the accompanying drawings, a preferred embodiment of thefourth invention will be described below.

FIG. 29 is a perspective view of a preferred embodiment of a verticalheat treatment system according to the fourth invention, and FIG. 30 isa perspective view of this vertical heat treatment system viewed from adifferent angle from that in FIG. 29.

As shown in these figures, the vertical heat treatment system 3001 is asystem capable of carrying out various heat treatments, such asdiffusion, oxidation or CVD, with respect to wafers W. The interior of acasing 2010 defining the contour of the vertical heat treatment system3001 is separated by partition walls 3012 and 3013 into a carriertransfer area Sa, a loading area (loading chamber) Sb and a heattreatment area Sc.

In the loading area Sb, the transfer of wafers W from the interior of acarrier 3014 to a wafer boat 3016, and the carrying of the wafer boat3016 in and out of a heat treatment furnace 3018 are carried out. Cleanair is supplied to the carrier transfer area Sa via a filter (notshown), so that the carrier transfer area Sa is maintained in anatmosphere of atmospheric air. The loading area Sb is separated as anairtight region in which an atmosphere of nitrogen gas (an atmosphere ofan inert gas or non-oxygen) is formed.

The carrier 3014 is a so-called closed type carrier, which housestherein a plurality of wafers W and which is closed by an FIMS(Front-opening Interface Mechanical Standard) door 3015. Specifically,the carrier 3014 is a portable plastic vessel capable of housing thereina plurality of, e.g., about 13 to 25, semiconductor wafers W having apredetermined diameter, e.g., a diameter of 300 mm, in a horizontalstate on multiple stages at regular intervals in vertical directions.Moreover, the carrier 3014 is formed with an outlet for the wafers W inthe front face portion thereof, and is detachably provided with the FIMSdoor 3015 for airtightly closing the outlet.

The front face portion of the casing 3010 is provided with a carriercarrying-in/out opening 3020 for carrying the carrier 3014 in and out bymeans of an operator or a transfer robot. The carrier carrying-in/outopening 3020 is provided with a load port 3022 for carrying the carrier3014 in or out of the carrier transfer area Sa. By means of a transfermechanism 3024 provided on the load port 3022, the carrier 3014 is movedon the load port 3022 to be transferred to the interior of the carriertransfer area Sa.

In the carrier transfer area Sa, shelf-like storage portions 3026 forstoring a plurality of carriers 3014 are provided above the load port3022 and above the side of the partition wall 3012. On the side of thepartition wall 3012 in the carrier transfer area Sa, a carrier mountingportion (FIMS port) 3027 is provided for supporting thereon the carrier3014 to transfer the wafers. In the carrier transfer area Sa, a carriertransfer mechanism 3028 is provided for transferring the carrier 3014between the load port 3022, the storage portion 3026 and the carriermounting portion 3027.

The carrier transfer mechanism 3028 comprises: a lifting mechanism 3028a which is provided on one side portion of the carrier transfer area Sa;a lifting arm 3028 b which is vertically moved by the lifting mechanism3028 a; an arm 3028 c which is provided on the lifting arm 3028 b; and atransfer arm 3028 d which is provided on the arm 3028 c for supportingthereon the bottom of the carrier 3014 to transfer the carrier 3014. Thepartition wall 3012 is provided with a door 3030 which is formed so asto have a shape corresponding to the wafer outlet of the carrier 3014and which is capable of being open and closed. By opening the door 3030while the carrier 3014 contacts the door 3030, the wafers W in thecarrier 3014 can be taken in and out of the loading area Sb.

In the heat treatment area Sc, there is provided the heat treatmentfurnace 3018 for housing therein the wafer boat 3016, which holds thewafers W, to carry out a predetermined heat treatment.

Above the inside of the loading area Sb, a lid 3032 is provided so as tobe capable of being vertically moved by a boat elevator 3034 which is alifting mechanism. The lid 3032 can support thereon the holder 3016 of,e.g., quartz, which holds a plurality of, e.g., about 100 to 150, wafersW on multiple stages at regular intervals in vertical directions. Byvertically moving the lid 2032 by means of the lifting mechanism 3024,the wafer boat 3016 holding the wafers W can be carried in and out ofthe heat treatment chamber of the heat treatment furnace 3018. In thevicinity of the throat of the heat treatment furnace 3018, there isprovided a shutter 3026 which is capable of being open and closed inhorizontal directions for closing the throat when the lid 3032 is moveddownwards and when the boat 3016 is carried out after the heattreatment.

In one side portion of the loading area Sb, a boat stage 3038 which is aboat mounting portion is provided for supporting thereon the wafer boat3016 in order to the wafers W. Behind the boat stage 3038, a standbystage 3040 is provided for supporting thereon the wafer boat 3016 whichholds the wafers W.

In the lower portion of the loading area Sb, a boat transfer mechanism3042 is provided between the carrier mounting portion 3027 and the boatelevator 3034 for transferring the wafer boat 3016 between the boatstage 3038 the standby stage 3040 and the lid 3032.

The boat transfer mechanism 3042 comprises a first arm 3042 a capable ofbeing rotated in horizontal directions and moved in vertical directions,and a supporting arm 3042 b which is supported on the tip portion of thefirst arm 3014 a so as to be rotatable in horizontal directions andwhich is capable of supporting the boat 3016 in vertical directions, thesupporting arm 3042 b having a substantially C-shaped opening. Above theboat transfer mechanism 3042, a transfer mechanism 3044 is provided fortransferring the wafers W between the carrier 3014 on the carriertransfer portion 3027 and the wafer boat 3016 on the boat stage 3038.

The transfer mechanism 3044 comprises a lifting mechanism 3044 a, afirst arm 3044 b which is connected to the lifting mechanism 3044 a andwhich is rotatable in horizontal directions, a second arm 3044 c whichis connected to the first arm 3044 b and which is rotatable inhorizontal directions, and a supporting arm 3044 d which is provided onthe second arm 3044 c and which is retractable. The supporting arm 3044d comprises a plurality of, e.g., two to five, fork-shaped thin plates,and is movable while supporting thereon the wafers W.

The loading area Sb will be described below in detail.

The casing 3010 constituting the loading area Sb is provided with an airintake valve 3051, which is provided for introducing air, and an exhaustvalue 3052 which is connected to a nitrogen gas exhaust pipe (notshown), in order to replace the atmosphere of nitrogen gas at a positivepressure with an atmosphere of atmospheric air in the loading area Sb,which is separated as the airtight region by the partition walls 3012and 3013 in the casing 3010, during the maintenance of the system or thelike.

In this preferred embodiment, an atmosphere of nitrogen gas containingoxygen having a concentration of, e.g., 30 ppm or less, is formed byclosing the valves 3051 and 3051 and introducing nitrogen gas. As shownin FIG. 31, this concentration of oxygen is sampled and detected by anoxygen analyzer (not shown) from an oxygen concentration sampling port3054 a.

The vertical heat treatment system 3001 in this preferred embodiment isprovided with a safety mechanism utilizing an O₂ sensor 3054 which isprovided in the loading area Sb, in order to prevent the operator fromerroneously entering the loading area Sb in the state that theatmosphere of nitrogen gas is formed in the loading area Sb, i.e., inthe state that the concentration of oxygen in the area Sb is low, duringthe maintenance of the system or the like.

That is, as shown in FIGS. 32 and 33, the safety mechanism 3055 isdesigned to control the opening and closing (locking/unlocking) of amaintenance door 3056 (see FIG. 30) which is provided on the back faceof the heat treatment system 3001. The safety mechanism 3055 isincorporated into the casing 3010 of the system body, and is anelectromagnetic locking mechanism to which a control signal based on theconcentration of oxygen detected by the O₂ sensor 3054 is inputted via asignal line 3057. By this control signal, the protruding/non-protrudingof a lock pin 3058, which is engageable with a recessed portion 3060 aformed in the maintenance door 3056, is controlled.

For example, when it is detected by the O₂ sensor that the concentrationof oxygen in the loading area Sb is 19.5% or less, the lock pin 3058protrudes toward the maintenance door 3056 (engages the recessed portion3060 a), so that the locking state of the maintenance door 3056 ismaintained. In this case, of course, even if a knob 3059 is rotated, thedoor 3056 is not open. On the other hand, when it is detected by the O₂sensor that the concentration of oxygen in the loading area Sb is 19.5%or more, the lock pin 3058 is retracted from the maintenance door 3056to be in a non-protruding state (in which the lock pin 3058 does notengage the recessed portion 3060 a), so that the maintenance door 3056is in an unlocked state in which the maintenance door 3056 can be open.

The safety mechanism 3055 has a fail safe function, and is connected toa main control part (not shown) for generally controlling the of thesystem. That is, if the main control part detects that the system itselfdoes not normally operate for some reason, the lock pin 3058 ismaintained in the locking state even if it is detected that theconcentration of oxygen in the area Sa is 19.5% or more.

The safety mechanism 3055 is also provided with a key portion 3060 forforcing to release the locking state on the assumption that an emergencysituation may occur, regardless of the kind of the control signal basedon the concentration of oxygen, which is inputted via the signal line3057. Furthermore, of course, if a maintenance door is provided on theside face of the casing of the heat treatment system, such a safetymechanism may be applied to this door.

Referring to FIGS. 31, 34 and 35, a gas circulating cooling mechanismprovided in the loading area Sb of the vertical heat treatment system3001 in this preferred embodiment will be described below. Furthermore,FIG. 31 is a perspective view showing the structure of the gascirculating cooling mechanism 3061 viewed from the back face side of thesystem 1. In addition, FIG. 34 is a sectional view showing a topradiator 3066 and a bottom radiator 3070, which constitute the gascirculating cooling mechanism 3061, viewed from the side of a surfacefacing an FFU (Filter Fan Unit) 3065, and FIG. 35 is a viewschematically showing the flow of nitrogen gas by the gas circulatingcooling mechanism 3061.

As shown in these figures, the gas circulating cooling mechanism 3061 isprovided in the loading area Sb which has a closed structure (N₂ purgebox structure) in which an airtight region is formed by an atmosphere ofnitrogen gas. That is, the gas circulating cooling mechanism 3061comprises: the FFU 3065 which has a ventilating port 3063 in thevicinity of a throat of the bottom of the heat treatment 3018 arrangedabove the loading area Sb and which has a filter 3064 for purifying andsending nitrogen gas to the vicinity of the throat 3062 from the sidevia the ventilating port 3063; the top radiator 3066 which is arrangedso as to face the ventilating port 3063 in the vicinity of the throat3062; intake fans 3067 and 3068 for sucking nitrogen gas in the vicinityof the throat 3062 via the top radiator 3066; a circulating duct 3053which forms a nitrogen gas circulating path between the intake fans3067, 3068 and the FFU 3065 so that nitrogen gas sucked by the intakefuns 3067 and 3068 is returned to the FFU 3065 and which is partiallyarranged below the loading area Sb; an intake port 3069 which is formedin a region of the circulating duct 3053 arranged below the area Sb sothat a part of nitrogen gas sent by the FFU 3065 is sucked below theloading area Sb; and the bottom radiator 3070 which is arranged in thecirculating duct 3053 between the intake port 3069 and the filter 3064so as to cool nitrogen gas drawn into the circulating duct 3053 from theintake funs 3057, 3068 and the intake port 3069 to join.

The filter 3064 of the FFU 3065 comprises a filter for particle, whichfilters and collects particulate impurities in nitrogen gas. Moreover,the FFU 3065 is provided with a blower fan 3071 upstream of the filter3064 in the flow of nitrogen gas, i.e., below the loading area Sb, inorder to substantially send nitrogen gas from the ventilating port 3063via the filter 3064.

As shown in FIG. 34, the top radiator 3066 and the bottom radiator 3070are made of stainless to inhibit impurities from adhering to the wafersW to cause a chemical reaction (chemical contamination) or the like. Inthe top radiator 3066, only a principal part of a pipe 3072substantially having a cooling effect is exposed from the inner wall(side wall) of the casing 3010 in the loading area Sb so that waterdroplets do not adhere to the wafers W.

The pipe 3072 of the top radiator 3066 and a pipe 3073 provided in thebottom radiator 3070 are connected to each other by means of aconnecting pipe 3074. A refrigerant for removing heat from temperatureraised nitrogen gas passes through the pipes 3072, 3073 and theconnecting pipe 3074. In order to increase the quantity of heatexchange, the refrigerant preferably flows in the top radiator 3066 andthe bottom radiator 3070 in parallel. Moreover, on the surface of thepipes 3072 and 3073, a plurality of plate-shaped fins 3075 and 3076 areconnected so as to be perpendicular to the axes of the pipes.

As shown in FIGS. 33 and 34, the circulating duct 3053 mainly comprises:a pipe portion 3053 a for transferring nitrogen gas, which is introducedinto the top radiator 3066 via its front face, from the side portion ofthe radiator 3066 to the top; a pipe portion 3053 b for guiding nitrogengas from the pipe portion 3053 a toward the intake port 30, i.e., belowthe loading area Sb; and a pipe portion 3053 c, arranged below the areaSb, for supplying nitrogen gas, which is transferred from the pipeportion 3053 b, and nitrogen gas, which joins by the intake port 3069,to the FFU 3065.

That is, as shown in FIGS. 31 and 35, in the gas circulating coolingmechanism 3062 with this construction, nitrogen gas, which is sent inthe direction of arrow A from the ventilating port 3063 of the FFU 3065,i.e., to the vicinity of the throat 3062, passes over the top radiator3066 to be sucked in the direction of arrow C from the downstream of thetop radiator 3066 by means of the intake fans 3067 and 3068. Moreover,this nitrogen gas passes through the pipe portions 3053 a and 3053 b tobe transferred in order of arrows C, D, E and F.

On the other hand, a part of nitrogen gas, which is sent in thedirection of arrow A by means of the FFU 3065, travels directly towardthe lower portion of the loading area Sb to be transferred in directionsof arrows B1 and C1 to be sucked via the intake port 3069. Moreover,nitrogen gas downstream of the intake port 3069, i.e., nitrogen gasjoining in the pipe portion 3053 c, flows in the direction of arrow G topass through the bottom radiator 3070 to flow in the direction of arrowH to return to the FFU 3065.

As described above, the gas circulating cooling mechanism 3061 of thevertical heat treatment system 3011 in this preferred embodiment mainlycomprises: the FFU 3065 for sending nitrogen gas to the vicinity of thethroat 3062 through which the heat-treated wafers W are carried out; thetop radiator 3066 for removing heat of temperature-raised nitrogen gasin the vicinity of the throat 3062; and the intake funs 3067 and 3068for sucking nitrogen gas in the vicinity of the throat 3062 over theheat exchanger. Therefore, for example, when the wafers W heated to ahigh temperature in the heat treatment furnace 3018 are carried out,temperature-raised nitrogen gas in the vicinity of the throat 3062 canbe positively drawn toward the top radiator 3062 by means of the intakefuns 3067 and 3068 to remove the heat to cool the vicinity of the throat3062 of the heat treatment furnace 3018. Therefore, heat emitted fromthe throat 3062 of the heat treatment furnace 3016 can be effectivelyremoved, and the heated wafers W can be cooled. Thus, it is not fearedthat the temperature of the loading area Sb suddenly rises, so that itis possible to inhibit control parts, which are provided in the loadingarea Sb, e.g., which constitute a loading mechanism, from being damagedby heat.

In the gas circulating cooling mechanism 3061, the intake funs 3067 and3068 are arranged downstream of the top radiator 3066 in the flow ofnitrogen gas, so that nitrogen gas passing through the top radiator 3066to be cooled is sucked by the intake funs 3067 and 3068. Thus, it ispossible to inhibit the intake funs 3067 and 3068 from being damaged byheat. Moreover, in the gas circulating cooling mechanism 3062, the flowof nitrogen gas is regulated above the loading area Sb by the intakefuns 3067, 3068 and the duct 3053, and the intake port 3069, which isanother intake portion, is provided below the loading area Sb tosimilarly regulate the flow of nitrogen gas, so that it is possible toprovide excellent cooling effects while inhibiting particles from flyingin the area Sb.

While the present invention has been specifically described in terms ofthe preferred embodiments, the present invention should not be limitedto the above described preferred embodiments, but the invention can bemodified in various ways without departing from the gist of theinvention. For example, a glass substrate or an LCD substrate, otherthan the wafer, may be used as the object to be treated.

As described above, the heat treatment system according to the fourthinvention mainly comprises a ventilating unit for sending an inert gasto the vicinity of the throat, through which the heat-treated objectsare carried out, a heat exchanger for removing heat of atemperature-raised cooling fluid after the heat treatment, and an intakefun for sucking the cooling fluid in the vicinity of the throat over theheat exchanger. Thus, for example, when the objects heated to a hightemperature in the heat treatment furnace are carried out, the coolingfluid is blown onto the objects, and the temperature-raised coolingfluid in the vicinity of the throat is positively drawn toward the heatexchanger by the intake fun, so that the heat can be removed to cool thecooling fluid, the objects and the vicinity of the throat of the heattreatment furnace.

Therefore, according to the heat treatment system according to thefourth invention, it is possible to effectively remove heat emitted fromthe throat of the heat treatment furnace, and it is possible to cool theheated objects. Therefore, it is not feared that the temperature in acarrying-in/out region, in which the objects are carried in and out ofthe heat treatment furnace, suddenly rises, so that it is possible toinhibit control parts, which is provided in the carrying-in/out region,from being damaged by head, and it is possible to shorten the transfertime of the objects and improve throughput.

The invention claimed is:
 1. A method for transferring an object to betreated in a vertical heat treatment system having a holder supportingmechanism, the hold supporting mechanism comprising: a holder mountingtable for mounting thereon a holder for holding a plurality of objectsto be heat-treated, in a stacked state; and a holder position adjustingmechanism including a plurality of protruding portions corresponding tothe shape of a bottom plate of the holder, and a distance varyingmechanism for varying the distance between the plurality of protrudingportions, said method comprising: a mounting step of causing the holderto be mounted on a holder mounting table; a positioning step of movingsaid holder, which is mounted on said holder mounting table at saidmounting step, together with said holder mounting table, on a planealong a holder mounting surface of said holder mounting table toposition said holder at a predetermined position by varying the distancebetween the plurality of protruding portions with the distance varyingmechanism; a transfer step of transferring said objects to said holderwhich is positioned at said positioning step; and a returning step ofremoving said holder, to which said objects are transferred at saidtransfer step, from said holder mounting table to return said holdermounting table to a predetermined position.